Backset: "Backset" refers to the distance from the edge of the door to the center of the lock cylinder. Most US doors have backsets of 2 3/8" or 2 3/4". Our locks specifically specify backsets. Please be sure to select the right backset, unless our sets specify "Backset Adjustable" or "No Backset". **Please contact us if you have any further question on backset**