Fluidyne Polished Coolant Expansion Tank 1.25 Quart Featuring highly polished aluminum construction and meticulous TIG welding, there is no equal to the Fluidyne coolant expansion tank. Tank has a ¼” barbed fitting, 3/8” NPT side fitting and ½” NPT bottom fitting to make plumbing easy. Two ¼” mounting holes makes mounting this unit a breeze! Our tanks come with a high quality Fluidyne cap to complete the package.