The Tell CL100010 Brushed Chrome Storeroom Lever is rated a grade 2 and is designed to handle up to 400,000 cycles. UL Listed - 3 hour fire door. Door thickness range of 1 3/8-inch to 2-inch. Backset - standard 2 3/4-inch. The strike - T strike (1 1/8-inch x 2 3/4-inch). It has a 6 pin SCC keyway with 2 nickel keys per lock. The latch bolt is operated by rotating inside lever or key in outside lever. Outside lever always fixed.