The Sinister Diesel Thermostat Housing is a drop - in replacement for the OEM housing, with several advantages. It's anodized billet aluminum construction resists corrosion that often plagues OEM units. The Precision CNC machining and thick base plate ensure a complete seal for years to come. It's finished off in our Signature Sinister Blue to add some great looks to your engine bay. NOTE This thermostat housing is NOT compatible with Mishimoto thermostats, Features6061 T6 Billet Aluminum Construction, Longer life with a leak - proof seal, Tough, heat - resistant design, Blue Anodized FinishIncludes(1) Sinister Diesel Thermostat Housing, (1) O - ring seal.