2 threaded end caps for standard 1.15" inch thread adjustable dumbbells . Screw on and save your thighs from uncomfortable awkward dumbbell position when going to incline/bench and or shoulder press with adjustable dumbbells! Can handle up to 100lbs(+) safely .Each one tested before shipped. For controlled movements from thigh/top of knee . Do not drop. DO NOT LET THE CAP HIT THE FLOOR WHEN ATTACHED TO YOUR DUMBBELL. It will break. Lay your dumbbells down flat . Please make sure there is a inch of thread remaining past your plates so the cap can screw on all the way and grip properly.