Useful but cold
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.