BEDROOM FUNCTION: Recommend use on the living room or bedroom doors,locked by turn button from inside,outside can be unlocked by keyed. Brass keys with solid brass cylinder core is durable and secure for NCSEN standard. EASY INSTALL: This door knobs is simple installation just use screwdriver in 15 minutes,reversible for left or right handed,make sure the opening direction before latch installation. DOOR THICKNESS STANDARD: Fits most of size doors 1-3/8" to 1-3/4" thick, latch backset adjusts to either 2-3/8" or 2-3/4",you can remove the middle black part to adjust,with black part means 2-3/8"only. PERFECT MATCH WITH DEADBOLT:NCSEN has own designed on this door knob,you can install with any deadbolt lock in your home,whatever contemporary or vintage style. WARRANTY FOR CUSTOMERS: We promise 3-year warranty for mechanical and finish warranty 2-year with great after service.Installation question or quality problem kindly E-mail contact nicsen@foxmail.com. NCSEN Building Hardware has professional craft on lockset products,classic coastal Round door knob embellish your home Style.