This Push-Fit T-Connector will split the gas (or beer) line on your kegging system in two, allowing you to gas two kegs at the same time.
Note that this is 10mm diameter in and out - if you're after 8mm, you'll find it here.
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.