marathon watch ballistic nylon watch band, military grade with stainless steel, non-magnetic buckle (20mm | 11" length, black) marathon one-piece construction, military spec nylon watch band. original replacement strap for instruments using nylon straps from 16mm, 20mm, and 22mm wide. used for navigator, general purpose wrist watches, and wrist compass. it features a 316l stainless steel buckle with anthracite black ip coating. manufactured in accordance with watch strap specification mil-s-46383b.