Boundary 4.5 in. Fixed Partially Serrated Blade Survival Knife with Sheath 92737. No indoor gentleman's knife, this rugged blade is made for the outdoors and it shows. Covering the tang is an ergonomic handle made of an easy to spot, bright green polypropylene core with a textured grey thermoplastic rubber over mold that gives an excellent grip without compromising the strength of the handle.