Wasps, And Mud Daubers Pose A Serious Threat To The Water Heater On Your RV. They Can Enter Through The Water Heater Vents And Cause Serious Damage By Building Nests That Interfere With Air Flow. Camco (Model WH 500) Flying Insect RV Water Heater Screen Fits Atwood 6 And 10 Gallon And Suburban 6 Gallon Water Heater Vents. This Easy-To-Install Screen Will Help Ensure That Your Vent Stays Free From Costly Invasion By Unwanted Pests.