Protect your furnace and fan unit from flying insects. Wasps, mud dauber nests, birds and rodents pose a serious threat to your RV water heater, furnace and stove. They can enter through vents and openings, and cause serious damage by building nests that interfere with air flow. These easy-to-install screens will help ensure that your vents stay free from costly invasion by unwanted pests. Each screen includes installation tool and spring to secure screen in place. For Suburban furnace vent models 8535, 8531, 8525, 8940 DC and 8947 AC; Suburban louvered water heater vents; other water heater vents and most battery vents. | Camco Flying Insect Screen, 6-16 gallon water heater vents