Heavy Duty Construction -All Materials in the expansion tank are 100% food safe and FDA grade to make sure your water is tasteless, odorless, and contaminant free -The inside of the RO water tank is completely smooth to prevent damage to the bladder -The water storage tank is coated with a two-part epoxy primer and finished with polyurethane to resist damage even in the outdoors -The adjustable bladder within the water tank is made of high grade Chlorobutyl rubber and is completely airtight -The inside liner of the water filter tank is made of Virgin Polypropylene, the most durable liner even on a molecular level All the Water You Need A 6-gallon water pressure tank can hold 4.4 gallons of water. All tanks have a certain amount of their capacity used by the air bladder, which is necessary for drawing water from the water reservoir tank. Be Confident All components are high quality food-grade -Each RO tank passes extensive durability testing -A sealed brass air nozzle and o-ring sealed air valve caps means consistent air pressure -This reverse osmosis tank is designed to last over five years. Accessory Type: Tank. Brand/Model Compatibility: tankRo, Express Water. Pack Size: 1. Product Weight (lb.): 11 lb. Returnable: 90-Day. Product Depth (in.): 17.50 in. Product Height (in.): 12 in. Product Width (in.): 12 in. Accessory Type: Tank