Factory OEM Sure Grip replacement retainers standard and conical. Aluminum cup set include 8 standard and 4 conical retainers. Works on most brands of roller skates. Price is for 12 total cushion retainers and they are Made in the USA. Works on the following Sure Grip plates and trucks: Century, Century NTS, Super X, Probe, Probe NTS, Rock, Jogger, Avenger Aluminum, Avenger Magnesium, Avanti Aluminum, Avanti Magnesium, XK4, Cyclone, Cyclone NTS, and Invader.