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SEIKO SRP637 Prospex Stainless Steel Baby Tuna with Seiko 4R36, 24-Jewel Automatic Movement


The Seiko Prospex SRP637 is nicknamed the Baby Tuna. The protective shroud on this model is made from stainless steel and it increases the case diameter slightly to 46.5mm. The screw-down crown is now offset at the four o’clock position. Inside the case is the 24-jewel Seiko caliber 4R36 automatic (self-winding) movement that hand winds and is hackable. The powerful Seiko LumiBrite luminescent material used on the hands and markers gives the watch the same brilliant glowing properties that made the Seiko Monster such a huge phenomenon.

Lug width is 22mm. Case size is 46.5mm. Slightly domed Hardlex mineral crystal. Concave uni-directional rotating dive bezel helps protect the crystal. Seiko stainless steel bracelet with dual push-button deployant clasp (and diver extension). Solid screw-in case back. Water resistant to 200 meters. Day and date window.

Out of stock


Movement: Seiko 24-jewel Automatic (self-winding, hand wind)
Case: Stainless steel, 46.5mm x 13mm thick.
Back: Engraved screw-in back
Crystal: Domed Hardlex Mineral
Band: Seiko stainless steel bracelet, deployant clasp. 22mm
Water Resistant: 200 meters

Model: SRP637

All measurements are approximate and may vary slightly from the listed dimensions.