The entry-level Economy RO system is made with heavy-duty glass-filled polypropylene. It offers twice the strength and durability of ABS-constructed systems. The serviceable check valve eliminates spring noise. Clearly labeled inlets and outlets, double O-ring quick-connect fittings and a handy sump wrench make installation fast and easy. An NSF-certified storage tank, chrome faucet tubing and fittings are included.