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 Quick Release Buckled Strap is universal and will fit a wide range 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.