One quart aluminum tank is for cars with the manifold filler neck higher than the radiator top tank. Tank can be easily mounted as the highest point of the cooling system. Features include a heavy duty aluminum neck with an 1/8" NPT port for an overflow fitting, a 1/2" NPT bung on bottom, for a supply, and a 1/4"NPT fitting on the ALL36116 and a 3/8" NPT on the ALL36115 for a return line.