For divers looking for an ultra compact cutting tool, there's SCUBAPRO's WHITE TIP.

Made of 304-grade hard-tempered stainless steel, the WHITE TIP's blade is 2.56in/6.6cm long and provides both an excellent cutting edge and good resistance to surface oxidation. It includes a serrated edge -- best for sawing through rope, a conventional edge -- best for making clean slicing cuts, and an angled  Tanto tip, one of the strongest knife points available. A slot in the handle provides a place to string a lanyard.

The WHITE TIP is the perfect compact knife to attach to a hose or your BC as a primary knife, or stow in an easy-to-reach pocket as a back-up tool. Includes a locking sheath and kit for BC/hose attachment.