Most insect guards are normally not listed by size but rather by the name of the units designed to fit i.e. Suburban Roof vents are standard size and covers like Maxxie air fit most.
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Retired Navy
Jake my sidekick (yellow Lab) 10/04 - 05/20
2017 RAM 2500 CC 4X4 Cummins Diesel
2016 Flagstaff 26 FKWS
AF&AM & El Korah Shrine of Idaho