Worn by United States Air Force and United States Navy Pilots Precision Multi-Function OS80 Power Alarm Quartz Chronograph Features 1/20th Second, 60 Minutes, and 12 Hour Accumulated Elapsed Time Case in Solid Brushed 316L Stainless Steel Bracelet in Solid 316L Stainless Steel with Deployment Buckle and Double Lock Security Clasp Screw-Locked Crown and Screw-In Back Engraved Case Back Crown Shoulder Guard Unidirectional Racheted E6B Navigational Slide Rule Bezel for Calculation of Speed, Distance, and Fuel Consumption Tachymeter Super-LumiNova Advanced Illumination System on Hands and Indexes Alarm Indicator Sapphire Scratch Resistant Crystal Calendar Date Window Water Resistant to 100m (330ft) Diameter is 43.5mm, Thickness is 11mm and Weight is 4.8oz Every Watch has a Serial Number and comes with a 2 Year International Warranty