Grade 1 security single cylinder deadbolt with SmartKey cylinder. Cylinder design eliminates traditional pins and springs. Cylinder provides instant re-key functionality. SmartKey cylinder is a bump-resistant, higher pick-resistance lock. Included with each lock is the re-keying learning tool that allows the lock to be re-keyed in 3 easy steps. Fits all standard doors 1-3/4". Standard adjustable backset 2-3/8" - 2-3/4". Requires 2-1/8" diameter crossbore hole and a 1" diameter edge bore. Deadbolts are keyed alike in multiples of 4.