Finish: STAINLESS STEEL . Stainless steel 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: adjustable 2 3/8" to 2 3/4" standard Strike: T strike (1 1/8" x 2 3/4") standard Tubular construction