That’s about the 5th house we’ve done on that street with the same style vents in the last couple weeks. There’s insect screening inside those vents but that stuff is beyond useless. There are thousands of homes with attic vents like that, and the attics are typically hotter than most when I go in them so I don’t think the vents help much. Granted, ANY attic vent can be breeched by critters, we have seen them go in louvered vents, ridge vents, dome vents with fans, you name it. It just takes a whole lot longer to fix the slotted ones