Redefining the power of a sport watch with infinite possibilities. Introducing the Citizen Series 8 mechanical collection of modern timepieces for a modern world. The sporty designs with high-performance automatic movements make a powerful impression. Stand out in style with the refined, signature 831 mechanical watch that features a superior accuracy of -10 to +20 per day in a sleek, silver-tone stainless case and bracelet in both hairline and mirror finishes, a glossy blue dial with luminous hands and markers, and an anti-reflective sapphire crystal. This sleek, Citizen automatic men’s sport watch also features enhanced magnetic resistance to protect the movement against external magnetic fields, a 42-hour power reserve and water resistance to 100 meters. Caliber number 9051. Product Details MODEL NB6010-81L 5/24/2022 MOVEMENT TECHNOLOGY 9051 Automatic Powered by the release of a wound spring, mechanical movements never require a battery. Automatic mechanical movements have an oscillating weight that winds the spring with the motion of the wearer’s arm. CASE WIDTH (MM) 40 BAND TYPE Bracelet Stainless Steel CASE MATERIAL Silver-Tone Stainless Steel CRYSTAL Anti-Reflective Sapphire Crystal Impact and shatter resistant - anti-reflective coating deflects light CLASP Fold Over Clasp with Hidden Push Buttons DIAL Blue WATER-RESISTANCE WR100/10Bar/333ft [Swimming, Showering & Snorkeling] ADDITIONAL FUNCTIONS 42 Hour Power Reserve Antimagnetic 16000 -10~+20 s/d