It's time to do some preventive maintenance before it's too late.
With proper use of these unique items, you can eliminate the concern for costly repairs to the furnace as a result of blockage caused by mud daubers, wasps, mice, birds, spiders, etc. These screens are sized to allow free airflow to and from your furnace and are made of heavy rust resistant stainless steel. Installs easily with tension springs and installation tool (included). The Mud Dauber screens are essential companions to the RV furnace. Model M-200 is a rectangular screen 4" x 7-1/2".