Five Oceans One Way Valve Universal Primer Bulb, 3/8" & 5/16" COMPATIBLE with ethanol blended fuels, suitable for boats, RVs, tractors, and caravans. FOR USE with 3/8" fuel line hose ONE WAY Valve Orientation BULB DESING resists collapsing under vacuum and ballooning under pressure STAINLESS STEEL steeples clamps for leak- free performance Compatible with ethanol blended fuels Bulb Size: 3/8&#034; Exclusive check valves allow priming in multiple orientations without restricting fuel flow Bulb design resists collapsing under vacuum and ballooning under pressure Stainless steel steeples clamps for leak- free performance