Cast Iron Filter Adaptor is used for 200/250/260/300 Series Filters Inlet and outlet ports are 3/4" x 3/4", Nose Thread Size: 1”-12 (where filter screws on) Adaptor for mounting filter Suitable for gasoline, diesel, biodiesel, and ultra-low sulfur diesel (ULSD) Made in the USA. Not for use with aviation fuel. Cim-Tek has a mounting adaptor (commonly known as a filter head) to fit any need. This is a heavy-duty cast-iron material. For use with 250, 260, and 300 series filters. Made in the USA. Not for use with aviation fuel.