Bought this to replace one that I thought I had lost. YAY found it! Love this watch- The black and gray color scheme of this Khaki Field Mechanical is a subtle approach to military styling. It is powered by the exclusive H-50 handwinding movement which is housed in a 38 mm case. Triangular indexes with old radium color Super-LumiNova® and a durable NATO strap complete the package. https://www.hamiltonwatch.com/en-us/h69409930-khaki-field.html Reference : H69409930 Caliber : H-50 Collection : Khaki Field Movement : Mechanical Case size : 38mm Thickness (mm) : 9.5 Dial color : Grey Case material : Stainless steel Coating : PVD black Crystal : Sapphire Lug width : 20mm Power reserve : 80 hour Water Resistance : 5 bar (50m)/73 psi (164ft) Strap reference : H6006941071 Strap type : Nato Buckle type : Pin buckle Buckle width : 20mm The H-50 is an exclusive caliber specifically developed for our handwinding watches. The H-50 is available with or without a date function and has an extended power reserve of up to 80 hours, ensuring maximum reliability even when it is not wound for a few days.