Greenheck’s new HBTR-451 bubble-tight damper is designed to meet the requirement for zero leakage. The product features a silicone blade seal and double-gland axle seal factory-leakage tested to ensure bubble-tight performance up to 30-inch water gauge differential pressure. The HBTR-451damper is recommended for two-position shut-off applications including medical facilities and laboratories, food processing, military facilities, campuses, test laboratories, clean rooms, and microelectronic manufacturing.

Greenheck, P.O. Box 410, Schofield, WI 54476-0410, (715) 359-6171, fax (715) 355-2399; www.greenheck.com.