MilSub

Name: San Martin MilSub
Brand: San Martin

Entry-level Under $600

The San Martin SN004 MilSub is a 38 mm no-date military submariner homage, produced in collaboration with Watchdives, carrying a Seiko NH35A automatic movement inside a brushed 316L stainless steel case with a ceramic unidirectional bezel and a deep enamel-black dial lit by BGW9 blue lume.

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38mm

Case

200m

Water res.

13mm

Thick

46mm

Lug-to-lug

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Overview

Brand	San Martin
Reference	SN004
Category	Dive
Price guide	Entry-level · Under $600

Full specification

Specs

Case & dial

Diameter	38 mm
Lug-to-lug	46 mm
Thickness	13 mm
Lug width	20 mm
Water resistance	200 m
Crystal	sapphire with AR coating
Case material	316L stainless steel
Bezel	unidirectional dive, ceramic insert
Case back	solid

Movement & furniture

Type	Automatic
Caliber	Seiko NH35A →
Power reserve	41 h
Jewels	24
Lume	BGW9
Strap / bracelet	316L stainless steel oyster bracelet

On the wrist

Pick up the SN004 and the first thing you notice is how little it fights your wrist — at 38 mm and 46 mm lug-to-lug, it disappears under a cuff in a way most modern divers simply don't. The enamel black dial has genuine lacquer-like depth under direct light, and the applied indices pool with a cool BGW9 glow once the lights drop. The bezel is an outright highlight: polished outer teeth, brushed inner valleys, and clicks that feel confident and precise rather than vague or sticky.

Where the watch is honest about its price point is in the flat hands, which look slightly two-dimensional compared to the rest of the package, and in case brushwork that picks up scratches a touch faster than harder alternatives. The steel bracelet is solid and well-weighted with a milled, chamfered clasp, though the end-link edges can be a little sharp right out of the box. Neither flaw is a deal-breaker at this price — they're the sensible trade-offs that make the SN004 as strong a value proposition as it is.

Bottom line

A remarkably well-finished sub-$230 diver homage that punches well above its price in bezel action, case/bracelet fit-and-finish, and dial depth — the pick for compact-wrist collectors who want that 5513 military silhouette without the five-figure tariff.

Highlights

38 mm no-date MilSub homage
Seiko NH35A — hacking & hand-wind
BGW9 blue lume on dial & hands
200 m / sapphire with AR coating
Ceramic unidirectional bezel

Who it's for

Collectors with slimmer wrists (roughly 16–17 cm) or anyone who prefers a sub-40 mm diver will appreciate the SN004's compact, unassuming proportions. It works equally well as a first serious homage, a discreet daily-wear diver, or a travel piece for someone who wants a vintage military aesthetic at a fraction of the cost of the reference that inspired it.

Who should skip it

Skip it if you need a date complication, prefer a 40 mm-plus case, or expect meaningful secondary-market resale value.

Before you buy

Verify V2 vs. V3 — bezel click count differs between versions (120-click reported for V2; retailer listing for V3 states 90-click)
SN004 MilSub is distinct from the SN004-G (a 6200-retro homage with different case shape) — confirm you have the correct reference
Limited-edition Watchdives collaboration batches sell out; check stock status before ordering
Bracelet end-link edges can be sharp initially — consider a quick deburr or swap to a rubber/NATO strap at first wear

FAQ

Is the MilSub automatic or quartz?

The MilSub is automatic. The Seiko NH35A winds itself from the motion of your wrist, so it needs no battery. A full wind holds roughly 41 hours, so it keeps running overnight off the wrist; left longer it stops and restarts once you wear or hand-wind it.

What movement does the MilSub use?

The MilSub is powered by the Seiko NH35A from Seiko, an automatic caliber with 24 jewels, a 41-hour power reserve, and a 21,600 bph beat rate. Being automatic, it winds from the motion of your wrist and needs no battery.

How water resistant is the MilSub?

The MilSub is rated to 200 m. That is true dive territory: fine for swimming, snorkelling and recreational scuba diving, as well as all daily wear. Whatever the rating, avoid operating the crown or pushers underwater, and have the gaskets checked periodically to keep it reliable.

How big does the MilSub wear?

At 38 mm across with a 46 mm lug-to-lug and 13 mm thick, the MilSub wears as a versatile mid-size watch. Lug-to-lug is the measurement that really decides fit, since it sets how far the case spans the wrist — 46 mm suits most wrists, and smaller wrists especially should check that figure.

How does the SN004 stack up against the Seiko SKX it's often compared to?

The SN004 is noticeably smaller (38 mm vs. 42 mm) and uses the newer NH35A with hacking and hand-winding, versus the discontinued SKX007's non-hacking 7S26. Multiple hands-on reviewers rate the SN004's bezel action and case/bracelet fit-and-finish as superior to the SKX007, at a comparable or lower street price.

Is the SN004 reliable enough for daily wear given it's a Chinese-made homage?

The movement inside is a Japanese-made Seiko NH35A regarded as a robust everyday caliber. San Martin's case construction and quality control have improved substantially; multiple forum owners report multi-year daily wear without issues. After-sales service is limited to the reseller, so buy from a reputable retailer with a warranty.

Why does San Martin make both the SN004 and the SN004-G under the same prefix?

They share a reference prefix but are different watches: the SN004 MilSub homages the 5513-style military submariner (round lugs, plain dial), while the SN004-G uses a cushion-influenced 6200-retro case with different hand and dial options. The '-G' suffix distinguishes the latter throughout San Martin's catalog.

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