I got these to practice crack climbing generally, but most importantly in the gym. It's a huge hassle to tape up for one or two pitches of indoor crack when the rest of my workout is bouldering or regular gym climbing. These make it easy for me to hop on a few crack climbs and train throughout the winter. I just got them and have used them on a handful of pitches. They jam well, although some tape around the base of the hand over the gloves can be helpful. The gloves do not cover the outer portion of the hand that contacts the wall during a fist jam.
Matt the Amateur Climber