Heavy-duty nylon sheath has synthetic liner, metal reinforcements and lashing slots and The heavy duty nylon sheath is constructed with a hard synthetic liner and metal reinforcements. The sheath also includes a D ring, lashing slots, and a front mounted nylon storage pouch with Velcro closure. to Heavy Duty Nylon Sheath Lifetime Warranty. Smith & Wesson knives include a limited lifetime manufacturer’s warranty against defects in materials and workmanship.