Seiko’s official Save the Ocean collection lists both the SRPH75 and SRPH77 as Prospex Save the Ocean Special Edition models. The available official specifications are much fuller for the SRPH75: Seiko’s regional page identifies the pictured watch as SRPH75K1 and lists a 4R36 automatic movement, a 200 m diver’s rating and a 42.4 mm case. The collection page names the SRPH77, but does not establish its specifications. That means a reliable comparison must separate confirmed SRPH75 details from SRPH77 information that still needs verification.
What is confirmed about the SRPH75 and SRPH77?
Seiko’s Middle East SRPH75 product page identifies the pictured watch as SRPH75K1, while the product heading uses SRPH75. Seiko’s Save the Ocean collection page lists both “SRPH75 Save the Ocean Special Edition” and “SRPH77 Save the Ocean Special Edition.” This confirms that both references appear in the collection; it does not provide a full specification sheet for the SRPH77.
The labels “Monster” and “Tuna” appear in the supplied title, but the cited official pages do not establish them as Seiko’s official names for SRPH75K1 and SRPH77K1. Use the reference numbers when checking a listing or asking a retailer to confirm which watch is being sold.
SRPH75K1 specifications listed by Seiko
The following details apply to the SRPH75/SRPH75K1 only. They should not be transferred to the SRPH77.
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#1 Best Overall
- AUTOMATIC MOVEMENT – Powered by the Seiko Caliber 4R36 automatic movement with manual winding capability, 24 jewels, and approximately 41 hours of power reserve for dependable everyday performance.
- DIVER READY – Designed for underwater adventures with 200-meter water resistance, a unidirectional rotating bezel, screw-down crown, and screw case back.
- DURABLE CONSTRUCTION – Stainless steel case and bracelet paired with a Hardlex crystal provide durability for daily wear and outdoor activities.
- ENHANCED LEGIBILITY – LumiBrite hands, hour markers, and bezel improve visibility in low-light conditions, while the magnified day and date display offers quick readability.
- SPECIAL EDITION DESIGN – Features a textured blue dial inspired by Antarctic ice and penguin footprints as part of the Prospex Save the Ocean Special Edition collection.
| Specification | SRPH75/SRPH75K1 |
|---|---|
| Movement | Caliber 4R36, automatic with manual winding; 24 jewels |
| Power reserve | Approximately 41 hours |
| Functions | Stop seconds; day and date display |
| Case | Stainless steel; 42.4 mm diameter, 49.4 mm lug-to-lug and 13.4 mm thick |
| Crystal and visibility | Hardlex crystal with magnified glass; LumiBrite on hands, indices and bezel |
| Bracelet and fit | 20 mm lug width; bracelet length 198 mm; listed weight 186 g |
| Diver features | 200 m / 660 ft diver’s water resistance; unidirectional rotating bezel; screw-down crown; screw case back |
| Price shown | USD 520 on Seiko’s Middle East regional product page; this is a regional page value, not a universal current street price |
These specifications are published on Seiko’s SRPH75 product page. The page does not establish that the SRPH77 shares the same case, movement, bracelet, water-resistance rating or price.
What is not established for the SRPH77K1?
The cited collection page confirms the SRPH77’s place in the Save the Ocean Special Edition lineup, but the retrieved official material does not give its dimensions, movement, power reserve, crystal, bracelet or strap, water-resistance rating, regional price or availability. A side-by-side numerical comparison would therefore imply details that these sources do not support.
Rank #2
- WATER-RESISTANT: these water-resistant men's dive watches are ISO scuba-approved to depths of 200 meters
- AUTOMATIC: these self-winding, automatic men's watches are powered by your movement, with a power reserve of 41 hours
- STAINLESS STEEL: features a durable 43.8mm stainless steel watch case and bracelet.
- LUMIBRITE DISPLAY: this men's automatic watch features a highly-legible display with LumiBrite hands and markers
- 4R35 CALIBER: equipped with the reliable caliber 4R35 automatic movement, this accurate men's watch keeps precise time
Before buying an SRPH77K1, check an official regional Seiko listing or ask an authorized retailer to confirm the exact reference and its specifications, local stock, price and warranty. Do not assume the SRPH75’s 4R36 movement or 200 m rating carries over to the SRPH77.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Save the Ocean context
Seiko describes the Prospex mission as “to help protect the world’s oceans now and for future generations, and to secure this legacy for divers everywhere.” Its collection page says Prospex supports marine conservation through the Save the Ocean initiative. Seiko also describes the PADI Marine Debris Program as the world’s largest underwater citizen science movement and cleanup initiative, and reports that more than 70,000 divers have contributed to building an underwater seafloor-debris database. That count and characterization are Seiko’s published claims on the collection page, not an independently verified measurement.
Quick Recap
Rank #4
- PADI SPECIAL EDITION: Men's Prospex Sea diver featuring a PADI Special Edition design with a stainless-steel case and ceramic bezel display.
- AUTOMATIC MOVEMENT: Seiko 4R36 automatic movement offers manual winding, 24 jewels, day/date display, stop-second function, and approximately 41 hours of power reserve.
- 200M DIVER'S WATER RESISTANCE: Rated to 200 meters / 660 feet for diving, with a screw-down crown and screw case back.
- SAPPHIRE CRYSTAL: Sapphire crystal with magnifier and inner anti-reflective coating provides durable dial protection and improved readability.
- DIVER-READY FEATURES: 45mm stainless-steel case, unidirectional rotating bezel, LumiBrite hands, indexes and bezel, plus a secure three-fold clasp with extender.
Rank #3
- STAINLESS STEEL CASE built to endure with style, making this watch your perfect daily companion
- AUTOMATIC MOVEMENT for seamless precision in every tick of this watch
- SCRATCH-RESISTANT CRYSTAL to maintain a pristine look even with daily wear and tear on your watch
- LUMINESCENT HANDS for effortless readability in low-light conditions, ensuring you never miss a moment with this watch
- WATER RESISTANT DESIGN ensuring your watch is ready for any adventure, rain or shine
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.
