Kwikset 258Rct-S San Clemente Rectangular Single Cylinder Keyed Entry Deadbolt - BrassKeyed Entry (Single Cylinder) Function: This single cylinder deadbolt is keyed on the exterior with an associated thumb turn on the inside that can quickly and easily lock or unlock the latch mechanism. Single cylinder locks are most commonly used to secure entrances to a residence or place of business. Features: BHMA Grade 1 Designed for left or right handed doors Includes round square and drive in latch to fit all standard doors Includes round