PLEASE NOTE:Do not put the drill bit through the blue positioner directly,firstly use the postitioner to mark the fix place with pen ,then use the drill to make holes(check the last instructions image). High Quality:Concealed hinge jig is made of premium steel ,Perfect for standard 35mm concealed hinges,Especially designed to drill a hole on the door or desk gently and efficiently. Jig Drill Guide Set: The hinge jig can be adjusted for changes of door edge ,remove the dirty and debris quickly.This drill set is perfect for concealed hidden hinges and door locks. Package Included:1 *35mm Hinge Boring Jig,1 * Forstner Bit Positioner and 1 * Cutting head. Widely Application:Working efficiently for various drilling machines, such as drill press, gun drills,pistol drill, bench drill, vertical electric drills and so on.