Chelsea entry handleset with Lido lever interior and SmartKey single cylinder deadbolt. SmartKey cylinder eliminates traditional pins and springs. cylinder design provides instant rekey functionality. Smart Key cylinder is a bump-resistant, higher pick-resistant lock. Included with each lock is the rekeying learning tool that allows the lock to be rekeyed in 3 easy steps. Fits all standard doors 1-3/4'' up to 2-1/4''. Not designed to be used on 1-3/8'' thick doors. Standard adjustable backset 2-3/8'' to 2-3/4''. Requires 2-1/8'' or 1-1/2'' deadbolt cross bore hole, 2-1/8'' handleset cross bore, and 1'' diameter throw bolt hole.