Alde rubber connectors are made from ø21.4 mm epdm rubber, tested and used in central heating systems for over a decade. compatible with the 22 mm aluminium heating circuit, tube can be fitted to the rubber by hand. always ensure there is at least 3 cm of tube inside the rubber connector, and a fitted spring clip, for the heating circuit to be watertight. Dimensions: 120 × 122 × od 25.7 mm. includes clips.