(KC2375). Heavy-duty commercial passage 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. 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 at all times.