The Milescraft Hinge Mortise Kit allows you to replace doors without damaging the door or jamb. By routing matching mortises for hinges into the door and jamb, you won’t have to tear a hole in the wall just to hang a better wooden door. Durable steel frame with adjustable tabs allows for settings up to 1-3/4” and 1-3/8”. 1/2" Durable tungsten carbide tipped router bit included. Router bit with ball bearing eliminates the need for a bushing. Contains templates needed to rout hinge mortises. Five sizes included (2 ½”, 3”, 3 ½”, 4”, 4 ½”). Rotate template to achieve 5/8” radius or 1/4? radius.