The Spin Doctor Tile leveling system features a patented free-spin design that allows the cap to spin down the spacer screw with minimal effort. This allows installers to tighten the cap with only one hand, which is especially useful for installing large format tile. The caps and baseplates are sold separately, the caps are reusable for multiple jobs. The anti-friction shield provides maximum downward pressure, prevents joints from shifting, and also stops thinset from coming up between the joints and getting in the cap. Does not fit 3/16″ Spin Doctor Bases. Comes in 100 pc. quantity.