This 6mm size is a larger size normally either used for gas or long draw keg systems.  Its not recommended for direct draw kegerators as it does not apply much flow resistance. If you did use this beer line in your kegerator you will need about 6-8meters of beer line to get the adequate flow resistance and for this reason we would normally recommend the smaller 5mm or 4mm ID lines for Kegerator setups. Sold per metre.