It works different than the American made stick or snail type cappers, the sturdy head of the Polish capper requires that you firmly seat the cap on the nipple before releasing it & moving to the next nipple.
This is now my primary capper for shooting all of my percussion firearms.
If your interested in checking it out go to his website at polishcappers.com , he has a couple of good videos on how the capper works & is a good communicator with his customers.. Photo shows what it looks like & how nicely the cappers head fits in the nipple recess on my old 58 Remington.
Chuck