Three 4000L / 1000 gal. variable capacity tanks. Buy one, or better yet, buy all! These were built by Ripley Stainless. Heavy duty stainless with three 1.5 TC ports, One racking wand, racking door, thermowell, etc. These are not the cheap tinny vct tanks that you often see imported. These come with thermostat and electric control valve to maintain extremely consistent temperatures. Two glycol jackets per tank. Can easily be switched to run either lower or both cooling jackets, depending on how much wine you have in the tank. Really nice when only half full, so that upper portion of tank doesn't have condensation running down onto the top of the lid gasket.