The Grivel Trigger can be attached to the shaft of nearly any ice tool for added support while climbing. This highly adjustable attachment allows easy matching for mixed climbing, a place to choke up on your tool, and protection for your knuckles from bashing into the ice. The yellow fits shafts up to 20 x 30mm and the black fits larger sizes.
When I wanted to use my Quarks leashless, I attached these triggers (the Large fit well). The trigger gives an awsome feeling to the tool, and makes leashless climbing feel much more secure (when resting, the tool can just hang from your pointer finger). I highly recommend this attachment for anybody looking to turn a steep ice tool into leashless. The trigger can put extra strain on tendons, though, so it is recommended to keep the trigger low enough so that it does not separate your pointer finger too far away from the rest of the hand.
Added these to my Simond Naja Cup's (similar to Petzl Quarks). Coincidentally, I lost one leash so I spent the weekend climbing leashless. These do add some control and strength for climbing leashless. They do make your index finger cold faster too. Only my index finger was getting cold this weekend (air temp ~10 deg). I'll keep using them until I find my leash, and hopefully it warms up next time I go climb.
These triggers came on my Taa-k-oons. It adds to my hang time and delays the pump by distributing the pressure between index finger (trigger) and pinky (horn). The problem is it changes the swing so the tool pivots on your index finger instead of the pinky. It is no big problem on a hacked up climb where you are mostly hooking, but on fresh ice the funky swing over stresses my index fingers. Also the trigger gets in the way when I flip the tool around to hammer pins. I dont use the triggers any more.
If your one of us who finds your fingers twitching when climbing with a leash, sounds like you need a trigger. Two sizes to match any grivel tool, i put mine on my rambo evo 2's. I have large hands and never expierenced any stress on my finger while swinging into new ice. while the tool is turned around the trigger can get in the way of swinging the hammer or adze. kinda sucks but a sacrifice im willing to make.