Redhorse Performance 4910 Series water neck assemblies offer solution upgrades for your coolant outlets. These thermostat housings, or "water necks" as they are also called, make an excellent option for replacing worn or damaged of the stock engine coolant water outlet-or for creating custom color combinations at a minimal cost. RHP's thermostat housing assemblies are precision-machined from aluminum and are available in several styles, with O-ring gaskets to eliminate leakage, and offered in choice of clear, or blue, black, or red anodized finishes.