The OSK I has a massive blade which is combined with an extra large handle. This provides two different ways of grip: acloser to the rear end, with enhanced power for chopping tasks, or choked up, for more power when whittling, and for better control. The blade has an unusual shape as well. It has a recurve part for work like removing bark, and a wide spine that can be hammered on to apply extra force. The handle spine extends in a straight line to the point, allowing the knife to be used as a spear when attached to an appropriate shaft. A handguard keeps the fingers away from the edge. The blade, made of 440C stainless steel with a black protective coating, has a tang with full length, for greater stability: it extends all the way from the point to the lanyard hole at the rear. The polymer handle has slip-resistant rubber inlays. When not in use, the OSK I is protected by a nylon sheath with a plastic inlet. The sheath has one long loop and four narrow transverse loops for the belt.