Eshopps 3 Foot X 1 Inch Id Flex Hose Durable flexible hose (Length: 3', Connector outside diameter: 1.326", connector inside diameter: 1.188"). For use with all the PF-Series, WD-Series, RS-Series, R-Series, ADV-Series, DLX/PRO-Series boxes. Flex Hose is excellent for use as a drain hose in sumps. Wet/dry filters or other aquarium applications.