SteelDive's turtle-case divers share one shape — the cushion case descended from Seiko's 6105 "Captain Willard" — but the SD1970X, SD1974, SD1977T and SD1970W are not the same watch in different straps. The case size changes, the movement changes, and so does what you get for the money. This guide puts all six models' specs next to each other, which no listing anywhere currently does, so you can pick the right one for your wrist and your dial before you order.
Verdict: buy the SteelDive SD1970X or SteelDive SD1974 for the classic 43.8mm cushion case; buy the SD1977T Slim Turtle if your wrist is on the smaller side.
Best Willard look: SD1970X, $187.99 — nylon or rubber strap, 20mm lugs.
Best 43.8mm turtle on a bracelet without a day display: SD1974, $157.99 — steel bracelet, five variants, and no day wheel on the dial (the day-date SD1970W is $8 cheaper if you want one).
Best for smaller wrists: SD1977T Slim Turtle, from $165.99 — 42mm case, 13.45mm thick.
Best for a day-date: SD1970W, $149.99 — NH36 movement, day and date.
Skip it if you want a case smaller than 42mm or thinner than 13.45mm — none of these six goes below that.
What makes a "turtle" dive watch?
A "turtle" is dive-watch shorthand for Seiko's 6105 and 6309 cushion-case divers from the 1970s, named for their rounded, asymmetric outline. The SD1970X, SD1974, SD1977T and SD1970W all borrow that shape, and all four are built around a Seiko NH35 or NH36 automatic, a ceramic bezel insert, a sapphire crystal and 200m of water resistance — the spec floor this family shares.
What is the SteelDive Willard?
The SteelDive Willard is the SD1970X, which SteelDive titles the "43.8MM Willard". The name comes from Seiko's 6105, nicknamed "Captain Willard" after the character who wore one in Apocalypse Now. The SD1970X puts that cushion case around a Seiko NH35, a ceramic bezel, a sapphire crystal and a 200m rating, at $187.99 on nylon or rubber.
The SD1970X is sold under the STEELDIVE name, not Seiko's, and is often searched simply as "SD1970" — it is a homage, not a fake, and the difference matters for what you can legally buy and resell; we cover that distinction properly in our guide to homage watches and the law. Seiko's own 6105-inspired re-issues have sold from roughly £1,000 and up, several times the $149.99–$187.99 asked for anything in this lineup, and that gap is the whole value case for a homage. Per the listings, the NH35 is a 24-jewel automatic with hacking seconds, hand-winding and roughly a 41-hour power reserve, and the SD1970W's NH36 lists the same 24 jewels and ~41-hour reserve with a day display added. Seiko's published accuracy tolerance for the NH35 is roughly −20 to +40 seconds a day. None of these six listings states a measured figure for its own watch, so plan around that range. For regulation and day-to-day behaviour, see the Seiko NH35 movement explained. You can browse the full range at the SteelDive collection or filter by automatic watches store-wide.
| Model | Movement | Case size | Key feature | Price | Who it suits |
|---|---|---|---|---|---|
| SD1970X | NH35 | 43.8 × 13.5mm | Nylon or rubber strap, 20mm lugs | $187.99 | Wants the Willard look off a bracelet |
| SD1974 | NH35 | 43.8 × 13.5mm | Steel bracelet, 5 variants | $157.99 | Wants a 43.8mm turtle on a steel bracelet for $30 less than the SD1970X |
| SD1974B | Genuine Japan NH35 | 43.8 × 13.5mm (46.8mm lug-to-lug) | 3 strap options, stated lug-to-lug | $158.99–$165.99 | Wants the exact lug-to-lug confirmed |
| SD1977T Slim Turtle | NH35 | 42 × 13.45mm | Screw-bar 20mm lugs, black or yellow dial | $165.99–$175.99 | Smaller wrists, wants the slimmest case here |
| SD1970W | NH36 | 43.8 × 13.5mm | Day-date display, 6 variants | $149.99 | Wants day and date, lowest price of the six |
| SD1970S | NH35 | 43.8 × 13.5mm | Same NH35 and BGW9 + C3 lume as the SD1974; listed as 316L steel, though its gallery photo shows a bronze-toned case on rubber; 4 variants | $184.99 | Wants the SD1974's lume spec in a different finish, has confirmed the variant's case first, and will pay $27 more than the SD1974 |
SD1970X vs SD1974: which 43.8mm turtle should you buy?
The SD1970X ($187.99) comes on nylon or rubber and is marketed as the Willard; the SD1974 ($157.99) ships on a 316L steel bracelet in five variants for $30 less. Both share the same 43.8mm case, 13.5mm thickness, ceramic bezel and sapphire crystal — the real choice is strap versus bracelet, not case quality.
The SD1970X, $187.99 — 43.8mm, 13.5mm thick, nylon or rubber, 20mm lugs.
One quirk in the spec sheets: the SD1974's function list says only "Dive", but the SD1974 photo below shows a date window at 3 o'clock, and the SD1970X and SD1977T both list a date function, so the bracelet model appears to keep the date too. Because the listing itself doesn't state it, check your chosen variant's photo before ordering. The SD1974 does list five variants — 74RE-SS, 74YL-SS, 74OR-SS, 74QL-SS and 74WT-SS — all on the same steel bracelet at the same $157.99.
One honest caveat: on budget homage divers in general, the bracelet is the part owners criticise most, more often than the case or movement. If the bracelet is your main reason for choosing the SD1974, be ready to move it to a strap, and because its listing doesn't state a lug width, confirm that before ordering one.
The SD1974, $157.99 — same 43.8mm case as the SD1970X, on a steel bracelet, five variants.
Is the SteelDive SD1970X a good Seiko 6105 homage?
Judged against its own listing, yes: a sapphire crystal with AR coating, a ceramic bezel insert, a Seiko NH35 automatic and 200m of water resistance are all stated specs, which is a modern spec sheet wrapped in the 6105-style cushion case. It comes with a screw-down crown per its listing, plus a free extra strap and warranty card in the box, at $187.99.
What the spec sheet can't tell you is unit-to-unit consistency — bezel alignment, lume fill — which varies more within this price bracket than the numbers suggest. We go into that pattern across the brand in our honest assessment of whether SteelDive watches are good.
Is the 42mm SD1977T Slim Turtle the better fit?
If your wrist runs smaller, yes. The SD1977T drops to a 42mm case and 13.45mm thickness — 1.8mm narrower and 0.05mm thinner than the 43.8mm/13.5mm turtles here — while keeping the same NH35 movement, ceramic bezel and 200m rating. It starts at $165.99 on black rubber and runs to $175.99 on a steel bracelet, also available with a yellow dial.
The SD1977T Slim Turtle, from $165.99 — 42mm, 13.45mm thick, black or yellow dial.
"Slim Turtle" isn't just a marketing word here: the SD1977T's own spec sheet lists 42mm and 13.45mm against 43.8mm and 13.5mm on the SD1970X, SD1974 and SD1970S. The SD1977T shares the 20mm lug width stated for the SD1970X and the ceramic-bezel-and-sapphire floor of the whole family, and it fits screw bars at the lugs, which means a strap swap only needs a small screwdriver rather than a spring-bar tool. For strap sizing on any of these, see our lug width guide.
What is the lug width on a SteelDive turtle?
20mm, confirmed on the SD1970X, the SD1977T and the SD1974B's own spec sheets. The SD1974, SD1970W and SD1970S don't state a lug width figure in their listings. A 20mm lug takes the widest range of aftermarket NATO, rubber and bracelet options if you want to swap straps later.
Do you need the SD1970W's day-date?
Only if you want to read the day as well as the date at a glance. The SD1970W runs a Seiko NH36 rather than the NH35 used elsewhere in this family, and its spec sheet lists "Day-Date" functions, adding the weekday beside the date, where the SD1970X and SD1977T list date only and the SD1974 and SD1970S photos show a date window alone. It's also the cheapest model here, at $149.99.
The SD1970W, $149.99 — NH36 day-date, 43.8mm, 13.5mm thick, six variants.
Everything else matches: 43.8mm case, 13.5mm thickness, ceramic bezel, sapphire crystal, 200m rating, screw-down crown per its listing. It comes in six variants — 70W-HH-SS, 70W-GR-SS, 70W-BL-SS, 70W-HH-HR, 70W-GR-GR and 70W-BL-LR — all at the same $149.99.
What about the SD1970S and SD1974B?
The SD1970S ($184.99) shares the 43.8mm, 13.5mm-thick dimensions, the NH35 and the same BGW9 + C3 Super-LumiNova listed for the SD1974, and comes in four variants. Its listing states a 316L stainless case and a steel bracelet, but the gallery photo below shows a bronze-toned case and black dial on perforated rubber, so confirm the case finish and strap of the variant you want before ordering rather than buying on the photo alone. The SD1974B ($158.99–$165.99) is another 43.8mm model, listed with a Genuine Japan NH35, a stated 46.8mm lug-to-lug and three strap options. Both keep the 200m, sapphire-crystal, ceramic-bezel spec floor.
The SD1970S, $184.99 — 43.8mm, NH35, BGW9 + C3 lume, four variants.
The SD1974B's 46.8mm lug-to-lug figure is the only one stated outright across these six listings, and it's genuinely useful: lug-to-lug, not case diameter, decides whether a cushion case overhangs a smaller wrist. Its three variants — 74B-WT-HR and 74B-WT-KN at $158.99, and 74B-WT-SS at $165.99 — differ in strap and price, so check each variant's photo before ordering. Its listing doesn't state a screw-down crown the way the SD1970X, SD1974, SD1977T, SD1970W and SD1970S do, so we're not claiming one for it.
What size wrist suits a SteelDive turtle?
As a rough guide, wrists of about 6.5 inches (16.5cm) and up suit the 43.8mm models (the SD1974B's 46.8mm lug-to-lug, the only one listed, fits that range). Wrists under roughly 6.25 inches (16cm) should start with the 42mm SD1977T Slim Turtle, the smallest and slimmest of the six at 42mm and 13.45mm. None of these is a small watch.
Beyond the SD1974B's stated 46.8mm lug-to-lug, none of the other five listings gives a lug-to-lug figure, so we can't compare that number across the whole range. On wrists below roughly 6.25 inches (16cm), a 46.8mm lug-to-lug can reach the edges of a flat wrist, which is why the 42mm SD1977T is the safer first buy there. The SD1974's listing pitches it at sub-7-inch wrists, but its stated 43.8mm × 13.5mm case is identical to the SD1970X's, so if you want a bracelet on a smaller wrist, the SD1977T on its steel bracelet ($175.99) is the better choice. A soft NATO or rubber strap also lets a cushion case sit closer to the wrist than a stiff bracelet.
What's the difference between the Slim Turtle and the regular turtle?
1.8mm smaller across the case and 0.05mm thinner: the SD1977T Slim Turtle is 42mm and 13.45mm thick, versus 43.8mm and 13.5mm on the SD1970X, SD1974 and SD1970S. All four use the same ceramic bezel, sapphire crystal and 200m rating — size is the main difference between "slim" and "regular" in this range. The NH36-powered SD1970W shares the 43.8mm case but swaps in the day-date movement instead.
Which SteelDive turtle should you buy?
Buy the SD1970X if you want the Willard look on nylon or rubber and don't mind paying $187.99 for it. Buy the SD1974 if you want the 43.8mm turtle on a steel bracelet at $157.99 and don't need the SD1970W's day display. Buy the SD1977T Slim Turtle if your wrist is on the smaller side and you want the narrower 42mm case at $165.99 and up. It's only 0.05mm thinner than the others, so buy it for the width, not the thickness. Buy the SD1970W if a day-date display matters more to you than anything else here, at $149.99 — the cheapest of the six.
The SD1970S and SD1974B are the two to pick if a specific detail decides it for you: the SD1970S at $184.99, but only once you've confirmed which case finish your chosen variant ships in (its listing says 316L stainless steel while its gallery photo shows a bronze-toned case, and its BGW9 + C3 lume is the same spec the cheaper SD1974 and SD1970W list), or the SD1974B's published 46.8mm lug-to-lug and three strap options from $158.99. None of the six drops below a ceramic bezel, a sapphire crystal (AR-coated on all but the SD1974B, whose listing doesn't say), or 200m of water resistance, so there's no wrong spec-sheet choice in this family — only the strap, the price and the wrist you're buying for. See the full range in the SteelDive collection.