Arrow D64 Classroom Deadbolt. The Arrow D Series deadlocks are engineered to perform under the most extreme conditions where security is critical. Our Grade 1 extra heavy duty deadlock surpasses the demands of industrial, institutional and commercial applications. Housing–Two-piece housing, with free-spinning outer ring to prevent wrenching. Concealed mounting screws are standard on double cylinder functions. Deadbolt–1" (25.40mm) throw, solid steel deadbolt with hardened, free spinning, steel pin & insert. Backset–2-3/8" (60.32mm), 2-3/4" (69.85mm). Deadbolt fronts–2-1/4" (57.15mm) x 1" (25.40mm) standard for 2-3/8" (60.32mm) backset, 2-1/4" (57.15mm) x 1-1/8" (28.57mm) standard for 2-3/4" (69.85mm) backset. Drive-in deadbolts are available. Doors–1-3/8" (34.925mm) to 1-3/4" (44.45mm) thick standard. Strikes–Supplied standard with the #346 wood frame strike and BX91D strike reinforcement. The #345 metal frame strike is optional. Handing–All functions are reversible. Cylinder, Standard–Solid brass, Arrow “A” keyway, 6 pin cylinder. Supplied with two nickel silver keys. Available in Schlage CS keyway and other competitive keyways. Cylinder Options–Accepts 6 or 7 pin, small format, interchangeable cores. Supplied less cores. Will accept Best ™ or Falcon™ type cores (except the E41). Certification ANSI A156.5, Auxiliary Locks, Grade 1 Underwriters Laboratories (UL and CUL) listed for use on A label or lesser doors when used in conjunction with a rated primary latching device