High quality die-cast aluminum thermostatic sandwich adapter with 3/8 inch NPT ports and an O-ring diameter of 2 3/4 inch to 3 1/2 inch, this adapter provides external oil lines to allow the addition of an engine oil cooler. It installs between the stock engine oil filter landing and the oil filter. Stock filter is retained. Designed to be used on engines with a 13/16 inch-16 filter thread. Kit includes sleeve nut and brass hose barb fittings.