Allstar overflow tanks can be easily mounted as the highest point of the cooling system. Features include a heavy-duty aluminum neck with an NPT port for an overflow fitting, a NPT bung on bottom, for a supply. Stainless steel and plastic tanks capture coolant overflow and recirculate it to the radiator. Aluminum tanks require an aluminum cap to twist on the filler neck. Inlet/outlet fittings accept 1/4 in. - 5/16 in. diameter hose, depending on tank style.