Hybrid Racing K-Series Adjustable Thermostat HousingStylish & Versatile Our thermostat housing was designed for customers looking for OEM quality parts that function beyond the constraints of factory parameters. The sculpted housing is machined from billet aluminum and then treated to a high quality black anodized finish. This thermostat housing is adjustable, allowing it to fit many engine and radiator combinations. For years, customers have asked us to create a reliable solution they could count on.