Seiko Prospex x Automatic ft. Professional Marinemaster Men Diver Round 300m Water Resistant Watch SLA023J1 SLA023 SLA-023 SLA-023J1 Explore the SLA023J1, a watch that initially resembles the Marinemaster 300 SBDX001 but has subtle differences. Featuring a sapphire crystal and ceramic bezel, it is gaining iconic status among enthusiasts and reflects its value despite previous perceptions. The SLA023J1 remains an excellent choice, complete with a comfortable rubber strap and a legacy honoring the SBDX017. Caliber Number / Movement 8L35 (automatic with manual winding capacity) Power Reserve / Accuracy Approximately 50 hours (+15 to -10 seconds per day) Crystal Sapphire crystal (anti-reflective coating) Luminous LumiBrite on hands, indexes and bezel Case / Band Material Stainless steel (super hard coating) case, ceramic bezel insert with stainless steel band (three-fold clasp with secure lock, push-button release with slide extender) Water Resistance 300m / 1,000ft diver Case Size Thickness: 15.4 mm Diameter: 44.3 mm Length: 50.5 mm Lug width: 20.0 mm Other Specifications Seiko Prospex x Automatic ft. Professional Marinemaster Made in Japan Additional silicone strap inclusive 28,800 vibrations per hour (8 beats per second) Unidirectional rotating bezel One-piece structure Screw-down crown 26 jewels Date display Stop second hand function (hacking mechanism) Regular timekeeping (analog display)