This Push-Fit fitting will allow you to connect 10mm OD line to keg couplers or any 5/8" thread.
Note that this is for 10mm diameter line - if you're after 8mm, you'll find ithere
They are extremely easy to use and allow you to simply push your beer and gas line straight into these fittings. No need to purchase clamps or tools. To remove the fitting, simply push in the collet and the hose can be removed. Fits 10mm outer diameter tube.