Color:Blue New high quality compression fitting from Enzotechnology is for the system builders who do not want to use hose clamps or zip ties. This will secure tubing on the fitting and make your system look great! It is compatible with 3/8" ID and 5/8" OD tubing and includes a special outer coupler for perfect sealing. Sold as a 4-pack. Model: TR-CFS-ID3/8-OD5/8-B-4P.