air volume damper 1 high efficiency,durable 2 easy to installation The introduction of volume control damper,air damper,volume damper NameModelFunction codeFunctionsspecificationShapeDiacharge fume valvePYF-1SDDC24V turned on,manual open,hand reset,out put opening signal≥200*200rectanglePYF-3SD≥Φ200roundDischage fume and fireproof valvePYFH-3SFDDC24V turned on,manual open,hand reset,out put ...