Arrow DC305AL Aluminum Size 5 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 5, fits interior door width 48" to 54" inches wide, and for exterior (and vestabule) door width 36" to 42" inches wide. For Parallel Arm, Size 5, fits interior door width 38" to 48" inches wide, and for exterior (and vestabule) door width 30" to 36" 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.