There are several items that are essential when putting together a Save-A-Dive Kit, Cylinder Valve O-rings, Fin Straps, Buckles, etc. One of the most important items is the Spare Knife Strap. This Rubber 20" (50.8 cm) Quick Release Buckled Strap is Universal and will Fit-a- Large-Variety of Knife Sheaths out there. Don't let a bad Knife Strap be the causes of you not carrying your Diver's Tool, always have a Spare. Strap is made of Depth Compensating Rubber, so your Knife won't get lose when your Exposure Suit Compresses Upon-Descent. Strap is equipped with Squeeze-Style" Quick-Release Buckle that is Non-Corrosive Impact Resistant Plastic for Long Life and Durability.