WATER WORKER G5L Expansion Tank, 2-Gallon Product Description 2 gallon, thermal expansion water heater safety tank, steel outer shell, polypropylene lined water reservoir, heavy duty butyl diaphragm that flexes, leak proof precharged air chamber, reduces pressure build up harmful pressure spikes, in closed water systems, temporarily absorbs expanded water overflow. This product adds a great value. Product is highly durable and very easy to use. This product is manufactured china. From the Manufacturer WaterWorker Water Heater Expansion Safety tanks work on the same principle as pressure tanks. However, the diaphragm flexes up and down due to the pressure from the water expansion from heat in closed loop hot water systems. i.e., in-floor heating systems and hot domestic water systems. When water is heated expansions occurs within the water lines of the house. Excess pressure can damage solenoids, faucet disc and lift the pressure relief valve in the water heater. The Safety Tank absorbs that pressure and extends the life of the water appliances within the house. Features Designed to meet the requirements of, and are listed by the National Sanitation Foundation (NSF) under ANSI/NSF Std 62 The Butyl diaphragm has seamless construction and is designed to flex rather than stretch and crease like bladder tanks The polypropylene liner for the water reservoir will not flake, chip, crack or peel and does not impart taste and odor to the water Diaphragm, liner isolate water from contact with deep drawn steel domed shell - twice as strong as rolled steel shell of same thickness A high gloss enamel finish protects tank from the elements Pre-charged to 25psi: please refer to product manual for proper pre-charge setting Designed to meet the requirements of, and are listed by the National Sanitation Foundation (NSF) under ANSI/NSF Std 62 The polypropylene liner for the water reservoir will not flake, chip, crack or peel and does not impart taste and odor to the water Diaphragm, liner isolate water from contact with deep drawn steel domed shell - twice as strong as rolled steel shell of same thickness A high gloss enamel finish protects tank from the elements Safety Tanks are installed with a solid bronze saddle on the cold side of the water heater Safety tanks can be combined for larger volume needs Backed by a 5-Year Warranty USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.