Five Oceans One Way Valve Universal Primer Bulb, 3/8" & 5/16" COMPATIBLE with ethanol blended fuels suitable for marine enviroment, boats, outboard engines, Rvs, and cars. FOR USE with 5/16" 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: 5/16&#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