8161- Series Cylindrical Ball Knob, ANSI- A 156.2, Series 4000, Grade 1, UL Federal Specification FF-H-106C. Lock Housing and Chassis - Cold rolled steel with zinc dichromate finish for corrosion resistance. Requires standard 2 1/8" (53.97mm) bore through door. Backset: 2-3/4",. Door Thickness: 1-3/8" to 2". Latch: Brass 1/2" throw, UL- Fire Rated for 3 hour doors,. Guarded Latchbolt on all locking functions. Latch front: 1-1/8" X 2-1/4" for 2-3/4" backset. Strike: 4-7/8"A.S.A. Cylinder: Solid brass 6 pin keyed 5, SC-1 keyway,. #1145 or AR-1 keyway. Locks will accept Lori plugs. Master key and Grand Master key available. Keys: 2 per lock. Handed: Non-handed. Finishes: US32D. Available Functions: Entrance, Passage. Trim: Knob 2-1/4" dia., Rose 3" dia.2 Stainless Steel Finish.