The SR 307 compressed air attachment is designed for connection to Sundström Air Purifying Respirator (APR)half masks and full face masks. This combination is a Supplied Air Respirator (SAR) in Continuous Flow mode (CF),for connection to a compressed air supply. The SR 307 is an accessory that enables a given facepiece to be usedas either a Air Purifying Respirator or a Supplied Air Respirator (SAR). The compressed air attachment is especiallyintended for applications involving heavy and sustained work in environments in which the pollutants have poorwarning properties or are particularly toxic.The SR 307 is made of a material which is not liable to give rise to frictional sparking, which enables the attachmentto be used in an explosive or flammable environment. The flow meter and warning whistle for temporary andcontinuous monitoring of the air flow rate are included. Control valve mounted on the user’s belt is included.