Fuel flow to your aircraft's engine can be compromised by insects or debris entering fuel tank vents. The Plane Sights remove-before-flight Fuel Vent Screen prevents contaminants from obstructing or contaminating the fuel system. The attached foot-long, florescent, and weather-resistant reflective streamer stands out equally well in daylight or darkness under all weather conditions, so it won't be forgotten during your pre-flight. Fits Cessna piston engine aircraft. Inside diameter of PVC sleeve is 0.365" (3/8")