Greenheck’s new heavy-duty HBTR-451 bubble-tight damper is designed to meet the requirement for zero leakage. The HBTR-451 features a silicone blade seal and double gland axle seal factory-leakage tested to ensure bubble-tight performance up to 30 in. wg (7.5 kPa) 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, 715-355-2399 (fax);