Wasps, mud daubers and rodents pose a serious threat to the refrigerator on your RV. They can enter through the vents and cause serious damage by building nests that interfere with air flow. Camco’s 42139 (Model RS 620) Flying Insect RV Refrigerator Screen is designed for new style Dometic refrigerator vents that have 20" long louver openings. These easy to install screens will help ensure that your vents stay free from costly invasion by unwanted pests. Includes (3) heavy-duty, stainless steel screens and (7) cable ties for installation. The screens measure 20" (L) x 1-1/2" (W).