IT'S BELIEVABLE. ..Finally a systematic way to field drill pillot holes before installing commercial hinges in wood doors. Just attach it to your power or battery drill and you're good to go. Every Professional Installer knows the importance of properly sized and aligned pilot holes. They are only as good as the one who makes them. The Kwik Drill is an excellent addition to the arsenal of the Door Pro who hangs doors for a living and wants to keep everything aligned. All three hinges drilled with just 3 pulls of the drill trigger !!! You'll be Doing More and Working Less ! What a bargain ! Available for 3-1/2" hinges with 5/8" radius corners, 4" hinges with square corners, 4-1/2" hinges with square corners .