Guard 1991 Polished Brass Keyed Entry Commercial Cylindrical Ball Knob Lock Set Lockset. Schlage SC1 Keyway 3 keys. Adjustable 2-3/8" or 2-3/4" backset (Backset is all metal!!! as can be seen in picture), interior knob push button, key outside, Tubular Type Construction, For Use On Interior Or Exterior Wood Or Metal Doors, 1-3/8" To 1-3/4" Thick. Finish: Polished Brass. Type: Commercial. Grade: 3. Function: Entry. Keyed Different. Keyway: SC1. Adjustable backset. 5 pin solid brass cylinder. Internal mechanism heavy gauge cold rolled steel. Positive push and turn button locking mechanism. 3" threaded rosette outside. Panic proof mechanism. Concealed mounting screws.