PLASSON threaded reducing bush - 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 1 x 3/4" INCH BSP THREAD ACTUALLY MEASURES APPROXIMATELY 1 1/4 x 1 INCH IN DIAMETER