WOODPECKERS HOOK STOP - The Hook Stop is a must have accessory for the Woodworking Rules. FLUSH WITH BOARD EDGE - Imagine being two or three feet away from the zero end of the ruler. Rather than stretching to try and keep the zero end flush with the boards edge, you can simply hook that end onto the board and away you go. INSTALLATION - The Hook Stop comes with 2 screws that thread right into the existing holes on your Woodpeckers Woodworking Rule (except 6" model) FITMENT - The Hook Stop fits all Woodpeckers Woodworking Rules (except 6" model)