If Wenoka (Palm Beach, Fla.) is still around they make excellent dive knives and have a good selection. I used to be a dive instructor years ago and here are some thoughts. What do you intend on using a dive knife for? The knife I carried was a Wenoka with a blunt tip,5" blade,stainless steel , a steel knob on the handle which was orange,easy to diassemble (I garunntee you even the best stainless will rust if you don't completly flush it with fresh water after every use in salt.)small saw serrations on one side and a plain edge with a line cutter on the other with a ball type detant in the handle for snapping in and out of the hard plastic sheath with rubber staps that I carried on my upper right leg so I could get to it when I needed it with little effort. What did I use it for you say? I pounded,pried,cut heavy and light nylon line (you don't hack underwater with a knife so a 5"-6" blade is enough),(the small saw serrations work great on nylon line from a lobster pot wrapped around a boat's prop),cut tons of monofiliment fishing line found on the reef and wrecks with the line cutter. (Ever get a hook w/80lb test line stuck in a neoprene dive suit wrapped up on a wreck?) I didn't stab sharks with it (or myself thank goodness due to the blunt tip which is great for scraping and saving your edge for cutting) I never lost it due to it's bright orange, fat, grooved handle (try useing a knife in dark, cold, water with gloves on when you can't see what your doing-you won't be conducting surgery with it) In short it was a big ,sturdy, sharpened pry bar for rough use. The steel didn't have to take a breathlessly sharp edge, just sharp enough to cut what I had to (cutting yourself free from kelp doesn't take a super sharp edge)and strong enough not bend while prying. The sheath was sturdy and well designed so the knife could be removed and replaced with one gloved hand without looking at what I was doing and the ball detant kept it in the sheath while upsidedown in a wreck. Lastly it didn't cost me an arm and a leg to purchase (about $35-40 in 1982) so if I lost it (still have it after hundreds of dives-faded orange handle and a ton of scratch marks on it plus a little rust)I would not be out big bucks. It was a tool pure and simple and saved the day many times over. Oh, if I needed something sharp to stick with (like killing fish I speared with a poke to the brain) I carried a $.99 ice pick on my speargun where it wouldn't get in the way and stick me or my equipment. (lost a few of those). A REAL dive knife is just that' one that is tough enough and designed by somebody that knows what a dive knife is supposed to do in an underwater environment. Hope this helps. Weldonk