Arrow DC304AL Aluminum (689) Size 1-4 Adjustable Surface Applied Door Closer, specially designed for retail or office This door closer is UL/cUL listed , its also UL10C listed for positive pressure to comply with UBC-72 (1997), it meats the requirements of ANSI A156.4, and it ADA approved. For regular arm and top jamb, size 1-4, fits interior door width 24" to 48" inches wide. This door closer features a cast aluminum body, a hardened steel rack and pinion, high tensil steel springs, staked valves, two non critical adjusting valves (sweep and latch) control closing speed, and a backcheck intensity valve.