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  • Will lock on single or identical double kernmantle ropes but not on braided ropes; fits single ropes from 10 - 11 mm and double ropes from 8 - 11 mm
  • Loads onto a rope without having to unclip; can be used as a back-up on descent or rappel when placed below the descender
  • A mechanical version of a Prusik hitch or Machard knot, the Shunt body must be held during usage on descent
  • Applies friction (braking) when device is released


View all Petzl Ascenders and Descenders

REI membership


Best Use Climbing
Fits Rope Sizes 8 - 11 millimeters
Weight 188 grams
Rated 2 out of 5 by from Limited use If you're looking for something to use for top rope self-belaying, look at the Petzl Basic. I've tried it with this device and feeding rope through required both hands at some points. Also, be sure not to grab the device if you fall, or device will not lock-up. While weighted, it's a bit difficult to unlock, too. Unless you're doing LOTS of rappelling, I would rather use a prusik for backup because of it's lighter weight. The main Pro for this device is that it can be easily slid up or down the rope. Most other ascending devices slide up fine, but need to be undone to slide back down.
Date published: 2007-09-16
Rated 5 out of 5 by from My new best friend Dont be fooled by reviews from those who dont know what they're doing; this is a great device for top rope soloing. I have already completed hundreds of lines on this device (from 5.8 to 5.12c) and find no real issue as long as one knows what theyre doing. In one review someone states that its "feeds rope difficultly", this is only a problem if you dont know how to fix line; after setting up the rope, stuff remainig rope into bag, tie it off (overhand) so that rope bag is hanging about a foot or so off the ground. This provides adequate wieght to insure feeding will never be an issue. I personally (I dont reccomend this)rarely back it up but if i do (generally on easy slabs where i could fall flat on the device) with overhand knotts between me and ground(if situation to do so presents itself) or usually with a prussik loop (note to newbies; a lot of sharma lovers and REI coulpes will tell ya its not safe, i however find it next to bp). NOTE; if you doubt the safety of top rope soloing, its probably not for you. I do not 'reccomend' it to anyone. Dont use the rope shearing devices like the BASIC or MINITRAXION, they are harsh on youre rope and i personally have sheared the sheath of an 'old' rope of mine whilst taking a nasty spill on a traxion while training on my buddys wall.
Date published: 2009-03-06
Rated 3 out of 5 by from Great for long rappels This device is best used on long rappels as a backup where a nylon prussic has a risk of fusing to the rope from the heat. It works great for this use. For top rope soloing, it has some use, however limited. It can't be used on overhangs and won't lock off if you fall on it or grab it in a fall. If you need to back off the climb, bring a prussic and strap for a foot loop to get up the rock or unweight the Shunt (if you carried a backup belay/rappel device). Otherwise, you can get stuck. If you take a fall, or stop to rest, expect to lose about at least a foot of progress as the carabiner rotates and the device locks off. The Shunt basically trails you as you climb. Weighting the rope works well on short climbs. However, on long climbs, the rope stretches too much and any weight lowers to the ground. If the weight lowers to the ground, the shunt stops sliding up the rope easily and climbing can become unsafe. For use in a 3 to 1 haul system in place of a prussic or teethed ascender, the device is a pain to get to work as it slips before locking off, limiting progress capture. It also doesn't unlock easily to slide up in a haul system either. I don't recommend using it in a haul system. A prussic works much better. Overall, it's a useful piece of gear, but you need to know its limitations and plan accordingly.
Date published: 2012-04-07
Rated 4 out of 5 by from Smooth feeding with minimal wear on rope This device works great for self belay top-roping and since it uses constriction of the rope as its form of braking, it puts minimal wear on the rope (compared to ascenders with tiny teeth). Just be sure to weight the rope, either by winding the coiled rope up onto itself or tying a sandfilled milk jug to it, this way the device slides easily up the rope with you and locks off solidly. The included instructions diagram well how to use.
Date published: 2007-10-28
Rated 4 out of 5 by from very handy I use it for self belaying but the trick is to add something as a chest harness to mantain the shunt the highest possible, and to add some weight to the end of the rope, that way the rope feeds smoothly trough the shunt, no hands needed. Also is very safe as a backup brake for rappelling.
Date published: 2008-03-26
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