You have selected the European version of the whole-house Aǹalemma unit, which was designed to fit into standard European plumbing systems. The European system uses millimeters as the main unit of measurement, and the whole-house Aǹalemma unit is fitted with the standard 28 mm piping (outer diameter). Before placing your order, please confirm that you’re using the European plumbing system in your home.  If you have any questions about the compatibility of your plumbing system with the whole-house Aǹalemma unit, please contact us at Installation of the whole-house Aǹalemma unit   A certified plumber is required for the installation of the whole-house Aǹalemma unit. There are two ways to connect the Aǹalemma unit, depending on the type of plumbing in your home. The two standard methods are press fitting and compression fitting. If the pipe size in your home differs from the pipe size of the whole-house Aǹalemma unit, your plumber will need to acquire a suitable reducer/adapter. For example, if your installations contain 19 mm piping, you will need a reducer that will connect your 19 mm piping to the standard 28 mm piping on the whole-house Aǹalemma unit. Aǹalemma Water is not responsible for the installation of the whole house unit.