The complete self-contained, battery-powered dl2700 is easy to install because it uses the same door prep (mounting holes) as most standard cylindrical knob sets. it can be used as a keyed or keyless lock system, with master key and unique master code capabilities. trilogy models employ "flex-drive" motor locking, there are no mechanical chambers to replace or solenoids to bind 100 user codes programmable keypad: passage function, master and management codes. one-time emergency access/service code. programmable delay entry (5-20 seconds) or key bypass non-handed, 12 button metal keypad, new clutch mechanism specifications: door: 1-5/8" to 1-7/8" backset: 2-3/4" dimensions: 8-1/4" h x 3-1/4" w cast aluminum body power: 5 "aa" alkaline batteries, with low battery alert keyway: sc1 certification: 3 hour u.l. fire rated deadlatch, grade 1 can be hardwired: relay output finish: 26d (dull chrome)