The SR 507 compressed air attachment is designed for connection to Sundström hoods SR 520/ SR 530/ SR 561/ SR 562, visors SR 570/ SR 540 EX, half mask SR 900, welding shield SR 590, helmet with visor SR 580 and welding shield/helmet with visor SR 584/ SR 580. This combination forms a breathing apparatus designed for continuous air flow, for connection to a compressed air supply. The SR 507 is an accessory that enables a given face piece to be used as either a protective device supplied with compressed air or a powered air purifying respirator (PAPR). The compressed air attachment is especially intended for applications involving heavy and sustained work in environments in which the pollutants have poor warning properties or are particularly toxic. The SR 507 is made of materials which are not liable to give rise to friction sparking, which enables the attachment to be used in an explosive or flammable environment. The flow meter and warning whistle for temporary and continuous monitoring of the air flow rate are included. Control valve mounted on the user’s belt is included.