The BuildPro adjustable magnetic spacers feature a magnetic base that holds securely to the BuildPro table. To adjust the height of the top rest, turn the screw clockwise or counterclockwise. The spacers have a 1 in. outside diameter and a 3/8 in.-16 threaded hole on the bottom to allow for even higher height adjustment. Adjusts from 3/4 inch to 1-1/2 inch.