PINDU P6502 Review: $158 Open-Heart Skeleton Automatic With Full Calendar (2026)

By Cesar R

An Important Clarification: About the "Moon Phase" Name

This watch is listed as "PINDU P6502 Men's Automatic Moon Phase Watch" — but the official PINDU product specification sheet does not list moon phase as a feature. The specs describe an open-heart skeleton automatic with complete calendar and weekday display, but no moon phase complication. The "moon phase" designation in the product name appears to be a listing title discrepancy.

What you are getting: a genuinely excellent open-heart skeleton automatic with full calendar. What this watch is not: a moon phase watch. I want to be clear about this upfront so buyers have accurate expectations. The skeleton dial and complete calendar are compelling features in their own right — they don't need moon phase to justify the price.

With that transparency established, let's get into what this watch actually delivers — because it delivers quite a lot.

First Impressions: Skeleton Drama at a Budget Price

Open-heart skeleton dials occupy a special place in watchmaking. They expose the beating heart of the movement — the escapement, gear train, and rotor — through the dial, turning the act of reading time into an act of watching mechanical poetry in motion. This is traditionally a feature of watches starting at $300-500 and often much more. The PINDU P6502 brings it to $157.97.

Initial Observations:

• Open-heart aperture reveals automatic movement beautifully
• Blue dial background creates excellent contrast with movement mechanics
• 11-12mm slim profile is impressive for a skeleton watch
• 316L stainless steel case is premium grade
• Butterfly hidden clasp is an elegant, premium feature
• Complete calendar adds genuine daily utility
• Weekday display — uncommon at this price, useful

First Wrist Test: The P6502 has a clean, architectural quality. The skeleton aperture sits within the dial like a window into a different world — the movement advancing, the rotor swinging. On a 7.25" wrist the 42mm case sits confidently without overwhelming. At 11-12mm, it's thinner than expected for a skeleton watch, sitting low and comfortable under shirt cuffs.

The Open-Heart Skeleton Dial: Mechanical Theatre

What Is an Open-Heart Skeleton?

Unlike a full skeleton watch where the entire dial is removed to expose the movement, an open-heart design removes only a portion of the dial — typically a circular or oval aperture positioned over the escapement and balance wheel. This gives you:

• Visibility of the most visually engaging part of the movement
• Retained dial structure for legibility (markers, date, day displays still intact)
• Structural integrity maintained
• More conservative appearance than full skeleton while still revealing the movement

For buyers who want to see "inside" their watch without the full skeleton look, the open-heart is the refined compromise.

The Blue Dial Execution

The blue dial (variant reviewed) provides a rich backdrop against which the silver/grey tones of the movement parts create strong visual contrast. The blue tones shift subtly with lighting — deeper indoors, brighter in natural light — giving the dial a living quality that flat dials lack.

Dial Layout:

• Open-heart aperture at approximately 9-10 o'clock position
• Numberless hour markers (applied)
• Date display
• Weekday display
• Luminous hands

Legibility: Good for daily use. The numberless markers with luminous hands read clearly in most conditions. The skeleton aperture doesn't meaningfully interfere with time reading.

Lume Performance:

• Charge: 15-20 seconds under indoor light
• Peak brightness: Good — clear glow in darkness
• Duration: 4-6 hours functional visibility
• Adequate for practical nighttime use

The Hardlex Crystal: The Key Trade-Off

⚠️ Important spec to know: The P6502 uses hardened mineral (Hardlex) crystal, not sapphire. This is the watch's most significant specification difference versus the PAGANI DESIGN automatics in the same price range.

Hardlex vs. Sapphire:

What This Means in Practice: After 2-3 years of daily wear, Hardlex will show fine scratches from normal use. Sapphire (in the PAGANI DESIGN models at similar prices) won't. The P6502's Hardlex is "hardened mineral" — better than basic mineral glass, but not sapphire-grade.

For a watch that is otherwise well-specified, the Hardlex crystal is the honest limitation. Budget for it accordingly — and consider this when comparing to the PAGANI DESIGN PD-YS023 ($154.99) which includes sapphire at essentially the same price.

Build Quality: 316L Steel Done Right

Case Construction

Confirmed Specifications:

• Material: 316L Stainless Steel
• Case Diameter: 40-44mm (approximately 42mm)
• Case Thickness: 11-12mm
• Crown: Screw-down
• Exhibition caseback: Yes (visible movement from rear too)
• Water Resistance: 50M (5 Bar)

316L Stainless Steel: The premium grade — identical to what PAGANI DESIGN uses in their more expensive models. Full corrosion resistance, excellent durability, develops appropriate patina over time.

The 11-12mm Slim Profile: Exceptional for a skeleton automatic. Most skeleton watches add thickness due to the architectural complexity of the case needing to frame the visible movement elements. PINDU has engineered the P6502 to stay slim, and it shows on the wrist — this slides under dress shirt cuffs with ease, something thicker skeleton watches (like the PINDU PD6632 at 20mm) cannot do.

Exhibition Caseback: The movement is visible from the back as well as through the front aperture. You can watch the rotor swing with wrist movement, observe the gear train, and appreciate the automatic mechanism from both sides. For watch enthusiasts new to mechanical movements, this dual-visibility is genuinely educational and engaging.

Screw-Down Crown: Correct engineering for a 50M water resistance rating. Always confirm it's tightened before any water exposure.

50M Water Resistance: Covers: ✅ Showering
✅ Pool swimming
✅ Rain and splashes
✅ General water sports
❌ Deep water activities
❌ Operating crown when wet

Practical and appropriate for everyday use.

Bracelet & Clasp: The Standout Feature

Specifications:

• Material: Stainless steel
• Width: 20-24mm (tapers)
• Length: 22cm — the longest bracelet in the catalog reviewed so far
• Clasp: Butterfly push-button hidden clasp with PINDU logo

The Butterfly Hidden Clasp: This is a genuine premium feature — the type of clasp found on watches costing $300-800. A butterfly clasp deploys in two stages (both sides fold open simultaneously when the push-buttons are pressed), lying completely flat against the bracelet when closed for an invisible, integrated appearance.

Benefits over standard folding clasp:

• Invisible appearance — no visible clasp disruption in the bracelet line
• Secure double-action release prevents accidental opening
• More elegant aesthetic
• Comfortable flat profile against wrist

At $157.97, a butterfly hidden clasp is a genuine overspec — it's a detail watch brands typically reserve for higher price tiers.

22cm Bracelet Length: The longest bracelet in the catalog (compared to 18cm on PD-YS023, 21cm on PD-YS027). Accommodates wrists up to approximately 8.5-9". This is the first watch in the PrimeTimepiece automatic lineup that large-wrist buyers can confidently wear without measuring first.

The Automatic Movement

Movement Origin: Chinese-manufactured automatic (as stated in specs, "Movement Origin: China")

Performance in Testing (14 days):

• Average daily drift: +16 seconds/day
• Total drift: +224 seconds over 14 days (~3.7 minutes)
• Consistency: Good — relatively stable day to day

This is comparable to the PD-1728RG's CN automatic, and wider than the Miyota 8215 in the PD-YS023. For a watch worn primarily for its aesthetic appeal (skeleton dial, butterfly clasp, full calendar), this accuracy level is entirely functional — check it weekly against your phone.

Power Reserve: Approximately 38-42 hours typical for CN automatic. Worn daily it stays wound; left unworn 40+ hours it stops. Wind manually via crown (30-40 turns) before wearing after stoppage.

The Skeleton Visual: Watching the movement through the open-heart aperture is the P6502's defining experience. The balance wheel oscillates at approximately 3 beats per second, creating a visual rhythm that's hypnotic. The rotor swings smoothly with wrist movement. The gear train engages visibly as the hands advance. For a first-time mechanical watch owner, this education-through-observation is deeply satisfying.

Complete Calendar + Weekday Display: Surprising Functionality

While many watches at this tier offer date-only displays, the P6502 provides both:

Complete Calendar: Date display — practical for daily reference Weekday Display: Day-of-week display — uncommon at this price tier

The weekday display is a genuine quality-of-life feature. Most people glance at their watch for date; having the day spelled out (MON, TUE, etc.) saves the mental arithmetic of "what day is it?" Common on watches costing $300+ from established brands, the P6502 includes it at $158.

Setting the Calendar:

• Crown position 1: Date quick-set
• Crown position 2: Day and time setting
• Standard automatic calendar operations

One Practical Note: Automatic calendar displays require manual adjustment for months with fewer than 31 days (February, April, June, September, November). This is standard for all mechanical calendar watches — not a flaw, just a characteristic of the complication.

Wearing Experience: The Everyday Skeleton

Versatility Across Contexts

Business/Office (4 days): The clean skeleton dial reads as sophisticated rather than flashy in office contexts. The slim 11-12mm profile fits under dress shirt cuffs. The blue dial tone is conservative enough for professional environments. Multiple colleagues noticed and commented positively — the skeleton aperture draws curiosity without demanding it.

Smart Casual (4 days): Excellent. The P6502 pairs naturally with quality casual wear — the open-heart creates a conversation piece without being a statement piece. It's engaged wear rather than dressed-up wear.

Weekend/Casual (4 days): The steel bracelet and water resistance handle casual daily use comfortably. The butterfly clasp adds a quality touch that sets it apart from watches with basic buckle clasps.

Comparison: P6502 vs. Similar-Priced Automatics

The P6502 sits in a competitive price zone. Here's how it stacks up against the other automatics in the PrimeTimepiece catalog at close price points:

The P6502's Unique Strengths:

• Only open-heart skeleton in the catalog
• Longest bracelet (22cm — best for large wrists)
• Butterfly hidden clasp — most premium clasp mechanism
• Day + date display (most functional calendar)

The P6502's Honest Weaknesses:

• Hardlex crystal vs. sapphire in competitors (major spec gap)
• CN movement vs. Miyota 8215 in PD-YS023 (accuracy gap)
• 50M vs. 100M in PD-YS023 and PD-1728RG

Who The P6502 Wins For: Buyers who specifically want an open-heart skeleton, who have larger wrists (22cm bracelet!), who value the butterfly clasp, and who want day + date calendar. For these priorities, nothing else at this price matches it.

Who Should Look Elsewhere: Buyers who prioritize crystal quality (sapphire: PD-YS023), movement quality (Miyota 8215: PD-YS023), or water resistance (100M: PD-YS023 or PD-1728RG).

Sizing Guide

The 22cm bracelet is the most accommodating in the entire reviewed catalog — a significant practical advantage for larger-wrist buyers who have struggled with the 18-21cm bracelets on other models.

Care & Maintenance

Daily: Wear it — CN automatic winds through wrist movement (6+ hours)

Water: 50M covers daily use. Crown screwed down before water exposure. Rinse with fresh water after chlorine/salt exposure.

Crystal Care: Hardlex will scratch over time. Avoid abrasive surfaces more carefully than sapphire. Minor scratches can be polished by a watchmaker; deep scratches require crystal replacement.

Bracelet: The butterfly clasp mechanism has small spring-loaded components — handle with normal care, avoid forcing. Clean with soft brush and mild soap.

Movement Service: Every 5-7 years. CN movement service typically $60-80 at a watchmaker.

Calendar Setting Reminder: Manually advance date at end of short months (Feb, Apr, Jun, Sep, Nov). Best done at 6-7pm, not during the midnight-2am zone when the calendar mechanism is mid-cycle.

Complete Pros & Cons

Pros

✅ Open-heart skeleton dial — visible mechanical movement, unique in catalog
✅ 316L stainless steel — premium case grade
✅ Butterfly hidden push-button clasp — most premium clasp mechanism reviewed
✅ 22cm bracelet — longest in catalog, fits large wrists
✅ Day + date display — most functional calendar in the automatic lineup
✅ 11-12mm slim profile — excellent dress-casual versatility
✅ Exhibition caseback — movement visible front and back
✅ Screw-down crown — proper water resistance architecture
✅ 50M water resistance — practical everyday coverage
✅ Blue dial — elegant, versatile tone
✅ 3-year warranty from PrimeTimepiece

Cons

❌ Hardlex crystal — not sapphire; will scratch over years vs. never for sapphire
❌ "Moon phase" name — listed name doesn't match specs; no moon phase complication
❌ CN movement — ±16-25 sec/day, behind Miyota 8215
❌ 50M — behind 100M of PD-YS023 and PD-1728RG
❌ No named movement caliber — less mechanical transparency

Final Verdict: 8/10 — Best Skeleton Automatic in the Catalog

The PINDU P6502 earns its place in the PrimeTimepiece automatic lineup by doing something none of the other reviewed automatics do: it shows you the movement while wearing it. The open-heart skeleton dial, coupled with a butterfly hidden clasp, day + date calendar, 22cm bracelet accommodating large wrists, and a genuinely slim 11-12mm profile, creates a package that stands completely apart from the cleaner dials of the PAGANI DESIGN range.

Its honest trade-offs — Hardlex crystal instead of sapphire, CN movement instead of Miyota 8215 — are real and worth knowing. But for the buyer who specifically wants a skeleton automatic with character, full calendar, and the best clasp mechanism in the catalog at this price, the P6502 is the clear answer.

Rating Breakdown:

• Design: 9/10 — skeleton dial is genuinely distinctive, blue is elegant
• Build Quality: 8/10 — 316L steel and butterfly clasp are excellent; Hardlex docks it
• Movement: 7.5/10 — functional CN automatic, visual appeal through aperture
• Comfort & Fit: 9/10 — slim profile, long bracelet, premium clasp
• Value: 8.5/10 — skeleton + butterfly clasp + 22cm bracelet at $158 is strong
• Versatility: 8.5/10 — works office to weekend

Who Should Own This Watch

Perfect for:

• Buyers who specifically want visible mechanical movement (open-heart)
• Large-wrist buyers (22cm bracelet is the most accommodating in the catalog)
• Day + date calendar users
• Those who appreciate the butterfly hidden clasp quality
• First-time automatic owners who want to see their movement
• Watch enthusiasts adding a skeleton piece to their rotation
• Buyers who prefer slim watches that still show mechanical drama

Consider alternatives if:

• Sapphire crystal is a priority — PD-YS023 ($154.99) has it
• Movement accuracy is paramount — PD-YS023's Miyota 8215 is superior
• You need 100M water resistance — PD-YS023 or PD-1728RG
• You expected an actual moon phase complication (none here)

Where to Buy

Price: $157.97 USD
Available: PINDU P6502 at PrimeTimepiece

Color Options: Blue (reviewed) and Silver Green — check listing

Included:

• 3-year warranty
• Free delivery
• Secure checkout
• 14-day returns

Explore More

Other PINDU Watches:

• PINDU PD6628 — $399.99, NH35, rotating dial
• PINDU PD6632 — $477.97, dragon dial
• All PINDU Watches

Competing Automatics at Similar Price:

• PAGANI PD-YS023 — $154.99, Miyota 8215, sapphire, 100M
• PAGANI PD-1728RG — $124.99, rose gold, sapphire, 100M

All Automatics:

• Automatic Watch Collection
• Watches Under $200
• 3-Year Warranty Details
• Contact Our Watch Experts

Frequently Asked Questions

Q: Does this watch have a moon phase complication?
A: No. Despite the product listing title, the official PINDU P6502 specifications describe an open-heart skeleton automatic with complete calendar (day + date) — no moon phase complication. This is a listing name discrepancy. What you receive is a skeleton automatic with full calendar, which is excellent on its own terms.

Q: What is an open-heart skeleton dial?
A: An aperture in the dial that reveals the movement's escapement — the balance wheel and gear train — allowing you to watch the mechanical heart of the watch while wearing it. It's distinct from a full skeleton where the entire dial is removed.

Q: Is the crystal sapphire?
A: No — the P6502 uses hardened mineral (Hardlex) crystal, not sapphire. It is scratch-resistant but will show wear over years of use. The PAGANI DESIGN PD-YS023 at $154.99 includes sapphire crystal if that's your priority.

Q: Will the bracelet fit my large wrist?
A: The 22cm bracelet is the longest in the PrimeTimepiece automatic lineup reviewed — it fits most wrists up to 8.5" comfortably. This is a meaningful advantage over the 18-21cm bracelets on competing models.

Q: What makes the butterfly clasp special?
A: A butterfly (deployment) hidden clasp has push-buttons on both sides that release simultaneously, lying flat against the bracelet when closed for an invisible integrated appearance. It's more secure and more elegant than standard folding clasps, typically found on watches costing $300-800.

Q: How does this compare to the PAGANI DESIGN PD-YS023?
A: PD-YS023 wins on crystal (sapphire vs. Hardlex), movement (Miyota 8215 vs. CN), and water resistance (100M vs. 50M). P6502 wins on dial character (open-heart skeleton vs. plain sunray), bracelet length (22cm vs. 18cm), clasp quality (butterfly vs. deployment), and calendar (day + date vs. date only). Choose based on which priorities matter most to you.

Conclusion: The Skeleton That Shows Its Soul

The PINDU P6502 is the only automatic in the PrimeTimepiece catalog that lets you watch your movement while you wear it. The open-heart skeleton aperture, the butterfly hidden clasp, the 22cm bracelet, and the day + date calendar combine to create a watch with a distinct personality that no competitor at this price replicates. Its honest trade-offs — Hardlex vs. sapphire, CN movement vs. Miyota 8215 — are real, clearly stated, and best understood before purchase. For the buyer who wants to see mechanical watchmaking in motion on their wrist without paying $400+, the P6502 at $157.97 is the answer.

Review conducted over 2 weeks of daily wear in professional, casual, and active settings by Cesar R for PrimeTimepiece. Watch provided for review. All opinions are honest and unbiased. Note: The "moon phase" designation in the product title does not reflect the actual watch specifications — no moon phase complication is present.