Derale 25772 Low Profile Pressue relief Sandwich Adapter with 3/8″ NPT Ports and 18×1.5mm Filter Thread. At only 1″ thick, this high quality aluminum low profile sandwich adapter features 3/8″ NPT ports and pressure relief valve and provides external oil lines to run an engine oil cooler while dropping the factory oil filter only 1″ lower than stock. Designed to be used on engines with a 18×1.5mm filter thread. Provides external oil lines for oil coolers without relocating the factory oil filter. Cast form high quality aluminum. Maintain factory equivalent oil filter. Built-in pressure relief. Low Profile Sandwich Adapter with 18×1.5mm thread size. Includes sandwich adapter, sleeve nut & O-ring. Specifications Adapter thread size 18×1.5mm. Adapter o-ring size 2-1/2″, 2-3/4″. Adapter thickness 1″. Adapter inlet size 3/8″ NPT