EVICLEAR WRAS Approved 1/2" Clear PVC Cross. Designed to take 1/2" Pipe - which has an outside diameter of 21.4mm.
Please note that clear PVC pipe has a slight blue / grey tinge to it and so should not be expected to be 100% optically clear. Clear pipe is typically used for sight glasses, process viewing and demonstration units. Other clear elbow fittings are available up to 8".