Make critical calculations and conversions with ease with this Hamilton Khaki Aviation Converter Automatic Men\'s Watch, designed with a bi-directional, rotating slide-rule bezel and the most advanced anti-magnetic hairspring alloy yet invented. The perfect pilot\'s timepiece. At A Glance  Presented on a brown leather strap with pin buckle fastening 42mm case size with 100m water resistance Black dial with baton hour markers with date window at 3 o\'clock Bi-directional, rotating slide-rule bezel Converts units, such as feet to meters or miles to kilometres, and currency Scratch resistant sapphire crystal glass Powered by the H-10 automatic movement with its superior anti-magnetic silicon hairspring Power reserve of 80 hours