Heavy-duty commercial storeroom ball knob. Satin stainless steel (US32D). Performance: Complies with ANSI A156.2. Series 4000, Grade 2 (400,000 cycles). UL listed for 3 hour fire door. Keying: 6 or 7 pin SCC keyway with 2 nickel keys per lock. Door range: 1-3/8" to 1-3/4". Backset: 2-3/4" standard. Strike: T strike (1-1/8" x 2-3/4") standard. Cylindrical, steel-coated with zinc dichromate (corrosion resistance). Latch operated by rotating inside knob or key in outside knob. Outside knob always fixed.