The Moroso Aluminum Coolant Overflow Tank Subaru WRX / STI is this direct bolt-in replacement coolant overflow tank. Fabricated aluminum was used for strength as factory tanks fail after repeated high-heat situations. This aluminum tank can be polished, chromed, painted, powder coated or left as-is for a race look. Includes billet aluminum filler neck and Moroso cap. The stock siphon hose drops right in.