The VANGUARD G4 PAPR ABEK1 Filter is a multi-gas cartridge designed to protect against a broad range of gases and vapours including organic gases, inorganic gases, sulphur dioxide (acidic gases), ammonia, and organic ammonia derivatives. Identified by standard colour coding (brown, grey, yellow, green), it must be used with the Vanguard particulate filter cartridge. When stacked with the particulate filter, the system can achieve a TH3 ABEK1P R SL rating. Sold individually.