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Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minuteThe Undive Dark Sea 500M is a dive watch introduced in 2017 by Hong Kong microbrand Undive, with a design inspired by the vintage Seiko 6105. Launch coverage describes a 45mm stainless-steel case, Seiko NH35 automatic movement and 500-meter water-resistance rating. Its reported prices are historical Kickstarter early-bird figures, not current prices; present-day production and stock are unverified.
What is the Undive Dark Sea 500M?
Fratello introduced the model on July 26, 2017, describing Undive as a Hong Kong microbrand and the Dark Sea’s design as drawing on the vintage Seiko 6105. The launch article presented two versions: a standard stainless-steel model and the Black Storm, distinguished by its black DLC-coated bezel. Fratello’s 2017 introduction is the source for the launch description and specifications.
What are the Dark Sea’s specifications?
The following are specifications reported in the 2017 introduction, rather than independent measurements. A 2018 review corroborates the principal dimensions, movement, crystal, lume and water-resistance rating.
| Specification | Reported detail |
|---|---|
| Case | Polished 316L stainless steel |
| Diameter | 45mm |
| Lug-to-lug | 50mm |
| Thickness | 15.4mm |
| Crystal | Domed sapphire |
| Bezel | Unidirectional; the 2018 review specifies 120 clicks |
| Water resistance | 500 meters, as reported in the launch coverage |
| Movement | Seiko NH35 automatic |
| Lume | Super-LumiNova BGW9 |
| Other case features | Screw-down crown and helium valve |
The 2018 review gives a 47mm measurement including the crown and says the 15.4mm thickness includes the crystal. Those measurement qualifications come from the review, not the launch article. Time to Blog Watches’ 2018 review also reports the 120-click bezel.
#1 Best Overall
- Founded in 1955, SEA-GULL created China‘s first mechanical watch. Today, it stands as the world’s largest mechanical movement manufacturer, producing one out of every four mechanical watch movements globally. This men‘s automatic watch is powered by the SEA-GULL ST17 automatic mechanical movement, running at 21,600 vibrations per hour. The exhibition case back allows you to see the movement at work.This watch is a good fit for mechanical watch collectors.
- The dial design stands out with a textured wave pattern and a fume gradient finish available in four colours: Lava Red, Dune Yellow, Ocean Blue, and Rock. The compass‑style small seconds hand adds a unique touch. With a 40mm diameter, 10mm thickness and 46.3mm lug‑to‑lug distance, this wrist watch for men fits most wrist sizes comfortably while keeping a clean, elegant look that draws in daily wear.
- The case and bracelet are made of 316L stainless steel, paired with a synthetic sapphire crystal that resists scratches well for everyday use. The 5 Bar water resistance makes it a practical mens waterproof watch for hand washing, rain, and daily splashes. The solid build has been recognised by many buyers. The presentation box version also includes a black leather strap, giving you more options to match your style.
- Weighing only 126g and featuring a 20mm bracelet width with a push‑button hidden butterfly clasp, this 6180 automatic watch feels light and comfortable for all‑day wear. The hands and markers have a luminous coating, so reading the time in low light is easy. These practical features make it a reliable option for those looking for a daily automatic watch.
- From the polished case finishing to the detailed dial, this SEA-GULL automatic watch offers a solid alternative to big‑name brands and serves as a great addition to a watch collection. A presentation box version is also available for those who prefer more refined packaging when presenting a watch as a present. It makes a thoughtful choice for Father‘s Day, Thanksgiving, Christmas, anniversaries, and other special occasions. For anyone searching for a quality mechanical watch for men, this model is well worth considering.
Which movement does it use?
The launch article identifies the movement as Seiko’s automatic NH35 and reports an approximate 41-hour power reserve, a 21,600-vibrations-per-hour beat rate, hacking and Diashock. These are published specifications, not results of independent testing. The 2018 review also identifies the NH35.
How do the stainless-steel and Black Storm versions differ?
The documented distinction is finish: the standard version has a stainless-steel bezel, while Black Storm has a black DLC-coated bezel. Fratello’s launch coverage does not establish differences in movement or water-resistance rating between them.
Rank #2
- Seagull movement : ST2130 automatic movement
- Case Thickness: Approx. 13mm
- Case Diameter: Approx. 44mm
- Lug-to-Lug: Approx. 50.2mm
- Crystal Material: Synthetic Sapphire
| Version | Documented finish | 2017 planned Kickstarter early-bird price |
|---|---|---|
| Stainless steel | Stainless-steel bezel | $436 |
| Black Storm | Black DLC-coated bezel | $460 |
These were planned campaign prices reported before the Kickstarter campaign was due to begin in early August 2017. The 2018 review also lists $460 for Black Storm. Neither figure establishes a current market value or asking price.
What straps were included?
The launch article says both versions came with an accordion-style diver strap and a leather strap. It does not state the lug width, so these details alone do not confirm compatibility with a particular replacement strap.
The Tool Desk
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- Titanium case with a black rubber strap. Uni-directional rotating bezel. Grey dial with skeleton hands and dot hour markers. Minute markers around the outer rim
- This chronograph features a sand-blasted grade 5 titanium dial with applied indexes coated with white Super-LumiNova that emits a blue light
- Swiss-automatic Movement
- Case Diameter: 44mm
- Diver’s 300m (984ft) Watch: in General, Suitable for Mixed-gas Diving
Is the Undive Dark Sea 500M still available?
Current production and official stock are unverified. A December 2020 forum post said the model was no longer being made, but that is a participant’s claim in second-hand-sale context, not an official production notice or evidence of availability in 2026. No current official seller or exact Amazon listing is established here. The 2020 forum post should therefore be treated as an unverified historical comment, not a definitive status update.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Don’t confuse it with UNDONE’s Aquadeep
The Undive Dark Sea 500M is not the UNDONE Aquadeep Submerge. UNDONE’s official Aquadeep page describes a separate titanium watch with 500-meter water resistance and an NH36 movement; those details do not apply to the Undive. UNDONE’s Aquadeep page identifies that separate model.
Quick Recap
Rank #4
- Automatic mechanical Watches for Men: ST2147 Movement .Automatic Winding.Three colours available:Blue/Silicone,Blue/Steel,Red.
- Business Dress Men Watches:Big face watch for men with calendar (day date).25 jewels for the ultimate in luxury.-Configure Your Perfect Fit: This timepiece is available in two distinct strap options to suit your preference. Choose the hard-wearing stainless-steel bracelet for unwavering elegance, or the versatile silicone strap for active comfort and a modern aesthetic.
- 6204 Seagull Mens Divers Watches Size：Band width:20mm/0.79in | Dial diameter:40mm /1.57in | Case Thickness:12.7mm/0.5in |Watch Strap length:180mm /7.09in
- 316L Stainless steel case:Scratch-resistant mineral crystal + 200m water resistance (20Bar) withstands rain, sweat & daily wear.The luminous function can read the watch in the dark environment.
- Sea-gull Watches started in 1955:Since its establishment, SEA-GULL has always insisted on independent innovation and research and development, and is committed to the research and development of high-quality movements and the research and development of China's original mechanical evening watches.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
