The DI system (all USA made) comes with a resin made by Purolite, all USA made resin highest quality level of resin for a mixed-bed resin. (Not from China). The DI system comes with a bypass pass valve (not an add on cost). 5yr parts warranty on the in and out valve. The DI system comes with a reducing coupling ( if needed) for 3/4″ to 1/2″.