Arrow Lock, MK12-DD-03-300-111, 605 US3 03 Bright Brass, Storeroom Always Locked Vestibule Function, Grade 2 Darrin DD Cylindrical Knob Lockset Lock Set, 2-3/8" Backset. Function: Storeroom - Dead locking latch bolt operated by key in outside knob or by operating inside knob. Outside knob is always inoperable. Keyway: Arrow A. Handing: Reversible. Door Thickness: 1-3/8" (34.92 mm) to 1-3/4" (44.45 mm). Backset: 2-3/8" (60.32 mm) standard. 2-3/4" (69.85 mm), 3-3/4" (95.25 mm) and 5" (127 mm) available. Lock Chassis: Cold rolled steel with zinc dichromate finish for corrosion resistance. Requires standard 2-1/8" (53.97 mm) bore through door. Latch: Brass with 1/2" (12.7 mm) throw. Latch housing is steel, with zinc dichromate finish for corrosion resistance. 7/8" (22.225 mm) bore in edge of door is required. Latch Front: Brass or bronze. Standard faceplate for 2-3/8" (60.32 mm) backset measures 2-1/4" (57.15 mm) x 1" (25.40 mm), with a flat front, for 2-3/4" (69.85 mm) standard faceplate measures 2-1/4" (57.15 mm) x 1-1/8" (28.57 mm), with a beveled front 1/8" (3.17 mm) in 2" (50.8 mm). Strike: Brass, bronze or stainless steel. Standard "T" strike measures 2-3/4" (69.85 mm) x 1-1/8" (28.57 mm). All strikes have a 1-1/4" (31.75 mm) lip to center dimension. Cylinder, Standard: Solid brass 6 pin cylinder with Arrow "A"� keyway, keyed to 5 pin for stock. Can be master keyed, grandmaster keyed and construction master keyed. Supplied with two 5 pin brass keys for stock.