Features:– Certified to: NSF/ANSI61, IS09001, CE, PED.– All tank models supplied with a seamless one-piece liner to provide strength, durability and leak-free performance .– Tank diameters from 7″ to 631″ and tank heights from 10″ to 83″.– Vacuum breaker supplied with tanks from 30″ diameter and above. Material– Tank body: FRP filament wound outer shell.– Liner: one-piece seamless PE inner liner, 0.15″ {3.0mm) to 0.3″ {7.6mm) corresponding to the tank diameter.– Base: FRP or reinforced PP.– Opening: 2.5″ & 4″ :reinforced plastic thread.