Carpet Knee Kicker Adjusts From 17 1/2 to 21 1/2 in Die Cast Aluminum Parts Tempered Steel Gripper Pins Dense Foam Rubber Bumper Construction Pins Adjust To Suit Different Types Of Carpet and Carpet Backings From Fully Retracted Position To 1/2 in Rubber Bumper Can Be Mounted in 4 Positions To Distribute Wear Evenly