lve FxF British Gas Approved Blue Handle Quarter turn full flow valve meets EN331 Thread parallel ISO 28 (formerly BS2779) – IMPORTANT NOTE, MOST PLUMBING PRODUCTS ARE STATED AS BSP IMPERIAL THREAD MEASUREMENT WHICH MEANS THAT ACTUAL DIAMETER OF THE THREAD SIZE IS APPROXIMATELY 1/4 INCH LARGER THAN THAT STATED IN BSP TERMS. FOR EXAMPLE THIS 3/4 INCH BSP THREAD ACTUALLY MEASURES APPROXIMATELY 1 INCH IN DIAMETER