faux wood decorative film, marble design decorative film, solid color decorative film PVCPROD , https://www.pvcprod.comJB / T 7228-94 This standard specifies the air volume control valve (hereinafter referred to as the air valve) classification, technical requirements, test methods, inspection rules, marking, Packaging and storage.This standard applies to the ventilation air conditioning system used to change the system air volume Rectangular valve, circular valve should also refer to the use. This standard does not apply to the dust valve with the system.