HoKa shut-off damper with hand lever, rotary knob, rotary knob infinitely variable, socket or flange, plastic molded part round with internal stop for connecting pipes in an exhaust air system by means of welding. As butterfly valve for adjusting and shutting off volume flows with internal EPDM seal. Inside diameter of the socket according to DIN 8062. Manufacturing process: up to Ø 400 mm made of injection-molded parts, from Ø 450 mm made of semi-finished products. Possible negative overpressure on request according to mechanical, chemical and thermal load.