Note first: If you have used a standard ascender/jumar, etc. this thing makes sense. If you haven't, what happens is this: You place the Ti-Bloc against your rope so the teeth point in towards the sheath and the direction you DON'T want it to go (i.e. if you are ascending a rope, the sharp ends point down). The string a biner through the pair of holes. When you pull down on the biner, the teeth push into the rope's sheath, and the Ti-Bloc, and anything attached to it, remain fixed in place.
First, anything by Petzl is good. Can't say enough about this little guy. A Ti-bloc, a prussik, and a couple locking carabiners will get you out of alot of jams. Went and finally practiced self-rescue and it was handy. It's a bit tricky in a self-rescue situation to thread a biner through the Ti-Bloc with one hand (assuming you're holding an injured leader with your brake hand), but thats more a personal dexterity issue than a Ti-bloc issue.
An illustrative story: Devil's Tower. Just purchased my Ti-Bloc ($21 Neptune Mountaineering, Boulder, Colorado) before driving up. As this trip was "Mellow" we did not bring aid gear, ascenders and all that, but the very light Ti-bloc was still on my harness. In the parking lot, some climbers who needed to get as stuck rope down asked for ascenders, and I got out this little marvel which they quickly retrieved their rope with.
The point is this: Ti-blocs weight-to-Usefulness ratio is huge (meaning good).
With a locking biner I have jugged/ascended many rope lengths with no problem.
The Petzl Tibloc is multifunctional: for rescues, hauling systems and rope climbing. Petzl Tibloc Features: Very small and lightweight. Chrome-plated ...More at Oregon Mountain Community
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