gvs rpb breathing air filter cartridgeAPF3100 The APF3100 is the original filter cartridge for the GVS RPB Radex breathing air filter. This cartridge uses a multi stage filtration system that removes moisture, oil aerosols, odours, and fine particles from compressed air. The Radex system filters particles down to approximately 0. 5 micron from the air stream, helping to provide clean breathing air for the user. AFC100 The AFC100 is a universal filter cartridge for various breathing air