Seiko Prospex SRP779K1 Self and automatic winding capabilities 21,600 vibrations per hour Power reserve: approximately 41 hours 24 jewels Day/Date calendar Screwdown crown and caseback One-way rotating elapsed timing bezel LumiBrite hands and markers Case Diameter 45.0 mm Meets ISO standards and is suitable for scuba diving. Caliber 4R36 Silicone Strap