A good carabiner or s-biner makes a great keychain -- it can clip to your belt or your bag so you never lose it, and you can keep more than one ring of keys on it. Plus, it hangs up nicely on hooks or magnetic holders with no fuss. Even so, Instructables user elplatt lost a keyfob from one because the carabiner latch came open one day. Committed to never let that happen again, he grabbed some heat shrink tubing, a heat gun, and went to work.
Full disclosure: I keep my keys on an s-biner as well -- it's not climbing grade, and it doesn't have the twist-lock that you'll find on climber's carabiners, but I have had the latch on one side pop open at the wrong time, leading me to pull out my keys only to find one of the rings -- and the keys attached -- still in my pocket. This hack fixes all of that. Elplatt slipped some heat shrink tubing around the top of his s-biner, closed it and slid the tubing down over the latch. Then, with a heat gun, he shrank the tubing so it would keep the latch shut. That's all there is to it -- no more lost keys or slipped rings.
Admittedly, you lose some of the benefit of having a carabiner or s-biner with this trick, since part of the beauty is how easy it is to add new rings, but if you have all the keys you're going to get, this is a great way to keep them all secure. Plus, if you ever need to take a whole ring off, heat shrink tubing is cheap enough to replace and easily cut off so you can open the latch. What do you think? Have a better solution? Sound off in the comments below.
Carabiner Keychain Mod: Stop Dropping Your Keys [Instructables]