Greenheck (Schofield, WI) now offers a heavy duty, rectangular industrial isolation control damper, Model HCD-221, which incorporates the square-blade design found on Greenheck’s bubble tight damper. The square-blade design enables the damper to provide shutoff with very low leakage in HVAC or industrial process control systems. With a flanged damper frame for easy mounting, Model HCD-221 features a blade seal mechanically fastened to the blade that is field replaceable and available with parallel or opposed blade action. A wide range of electric, pneumatic or manual actuators is also available. Model HCD-221 offers differential pressure up to 10 in. wg (2.5 kPa), velocity up to 4000 fpm (20.3 m/s) and withstands temperatures from -40 to 400 degrees F.