Heavy-duty commercial entry ball knob. Satin stainless steel (32D) finish. Performance: Complies with ANSI A156.2. Series 4000, Grade 2 (400,000 cycles), UL listed for 3 hour fire door. Keying: 6 pin SC4 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). Latchbolt operated by knob on either side. Outside knob locked by push-button from inside. Unlocked by key from outside or rotating inside knob. When knob locked by push and turn button from inside, key from outside or rotating inside knob does not unlock outside knob.