Wasps, Mud Daubers, Birds And Rodents Pose A Serious Threat To Your RV. They Can Enter Through The Water Heater Vents, Furnace Vents, And Battery Vents And Cause Serious Damage By Building Nests That Interfere With Air Flow. Camco RV Flying Insect Screen - WH 200 Fits Suburban Furnace Vents; Models 8535, 8531, 8525, 8940 DC, And 8940 AC, Suburban Louvered Water Heater Vents As Well As Most Battery Vents. This Easy To Install Screen Will Help Ensure That Your Vent Stays Free From Costly Invasion By Unwanted Pests.