PureWater Filters high quality USA standard approved water line. You can use this to hook up our Filter Kits (sold separately) to single-serve commercial brewers such as machines with a 3/4" to 1/4" adapter. This is also the standard size line for most refrigerators and ice makers and will allow you to easily extend or replace your current set up. LLDPE Polyethylene Tubing 1/4"OD, 0.170" ID. Compatible with plumb kits, commercial plumbable brewers, and mechanical water tank reservoirs, please note you will need the nozzle adapter, also sold separately.