This #2 jig automatically centers your hole in the middle of the board, and clamps to boards from 7/16 to 2-1/8 wide. The 4 holes are all threaded to take replaceable bushings (2 each 1/4, 5/16, and 3/8"), allowing you to drill multiple combinations (in 3/4, 1-1/4, 2, and 2-3/4" centers) without moving the jig.