Duncan performance rings add additional rim weight to compatible models increasing spin times! Aluminum performance rings are heavier than polycarbonate performance rings, so it is recommended that polycarbonate performance rings are installed in metal yo-yos and aluminum performance rings installed in plastic yo-yos. To install performance rings remove the installed side caps by disassembling your yo-yo by carefully pushing down on the bolt/axle. This will push the axle through and the side cap will pop out. Repeat this process for the other side by inserting the screw/axle into the axle hole of the other shell, and push downward. If the yo-yo is metal, a suction cup is needed to remove the side caps. Ages 12