If you install Best cylindrical lever locks, the HIT-12 is one installation tool you’ll want. Mounting the HIT-12 to the door is a breeze, and drilling perfectly positioned holes is accomplished in a matter of minutes. Unit has bushings on both front and back plate to allow drilling from both sides of door. Fits 1-3/8" to 2" doors with standard 2-3/4" backset or fits 3-3/4" and 5" doors with the HIT-BAK adapter.