316 stainless steel. On the exterior, they have a smooth edge over the competition. Unlike some others, there is no protruding cap to cause damage or be damaged by hull bumps or scrapes. Cap unscrews with hex head wrench for easy cleaning of filter and pressure testing of entire fuel system. Includes two silicone gaskets. 5/8" I.D hose, 7/8" maximum hull thickness, 1-3/8" installation hole size.
