The Brinks Commercial Double Cylinder Deadbolt lock is designed for interior or exterior doors where security is top of mind. The deadbolt locks and unlocks by key from the interior and exterior for added security. The deadbolt is equipped with a 6-Pin SC4 brass cylinder, saw-resistant bolt, and metal collar to resist prying and wrenching from intruders. It's made to fit wood or metal doors 1-3/8" to 2" thick and has an adjustable latch that fits a 2-3/8" or 2-3/4" backset. The Single Cylinder Deadbolt is also ANSI Grade 1 and tested to exceed 250,000 cycles and has a 3 hour fire rating (UL Listed) for commercial use. A square corner strike plate, 2 keys, mounting hardware, and installation instructions are included.