AIR ADMITTANCE VALVE DESIGNED TO ALLOW FREE ENTRY OF AIR INTO THE SANITARY PIPEWORK SYSTEM WITHOUT THE ESCAPE OF FOUL GASES INTO THE BUILDING. THE MAIN BODY OF THE UNIT IS MADE FROM PVC AND THE INTERNAL SEAL IS MADE FROM EPDM RUBBER.

GENERAL INTERPRETATIVE RULES 1 & 6 HARMONISED SYSTEM EXPLANATORY NOTES TO HEADING 3917 TEXT TO HEADING 3917