Locate the EXACT CENTER of your board Setup lock miter bits with ease No measuring or guesswork Quick & accurate setup of router table fence, centers groove in any board up to 4.5 inches width or thickness High precision sliding gears accurate to .001" Creates a 2-1 reduction of the sliding pin in relation to the thickness of your stock. This allows the user to center stock on the exact center of the router bit. Make perfectly centered mortises in one pass. Ideal for creating precision drawer slides in the center of your drawers & creating grooves for cabinet panels. Accurate setup of any manufacturers Lock Miter Bits. Made of high quality anodized aluminium. Saves time and reduces wasted stock. Includes wooden storage box.