Series Prospex Automatic Seiko SRPC23K1 Gender Man Case Stainless steel Stainless steel Strap Case Back Solid Hard Hardlex Crystal Glass Dial Color Black Silver Blue Automatic winding type with manual winding mechanism (No Need Battery Change) Cal.4R35 Diameter 45 mm 31 Date Calender Power Reserve 41 Hours 21.600 vibrations perhours Lumibrite hand and markers 23 jewels Screw case back Screw-down crown Three fold clasp with secure lock, push button release with extender Unidirectional rotating bezel Water Resistant 20 ATM (200 Meters)/20 Bar