FUNCTION INTRODUCTON: Entrance Function: Lock from inside manually(with thumb turn) and use a key on the exterior(each set has different keys) b>Double Cylinder Combination: Entry Lock with Double Cylinder Deadbolts provide double security,best match for back/front door,master room,cabin,utility room etc KEYED ALIKE/COMBO PACK: All keys are the same, all locks you received can be opened with the same key, minimize keys in your home. SPECIAL TIPS:√ Each lock has three keys, The more packs you buy, the more keys you will get. √ Same key in the same pack, different keys in different packs.each key is special-keys between different Pack are not universal, √ Please pay attention to the function of deadbolts, Some state may ban the use of double cylinder deadbolts in case of untimely escape,like fire/ flood /typhoon etcPRODUCTION INFORMATION: ●Product Name: Flat Ball Style Entry Doorknob Set (Exterior&Interior) ●Color&Finish: Polished Brass (Golden Finish) ●Material: Solid Steel(Latch), Zinc Alloy(Handle) ●Certification: ANSI Grade 3, Exceeds 200,000 cyles ●Package Include: Latch, cylinder, mounting screws, strike plate and installation instruction ●Dimension: Adjustable Latch with Backset: 60mm (2-3/8") or 70mm (2-3/4 ''); Fit all doors 35 to 45 mm ( 1-3/8 '' to 1-3/4 '')thick, ●Please kindly notice: The latch plate is square, and can't removable. ●Easy Installation:Tools for replacement installation, philips screwdriver.One-person project; no extra hands needed Tools required for new installation:hammer,chisel,measuring tape,power drill,removable tape,pencil.2-1/8〞hole boring saw,1〞 hole boring bit ,1/8〞 drill bit,Safety Googles.