This should be especially interesting for every owner of an RV that has nasty truma air vents positioned on the floor. This is the case for some Weinsberg and Knaus models, but will be present in others too I think.

The amount of dirt accumulating in those vents is awful. Totally closing the vents also does not seem like the best Idea. These things are a compromise to keep most of the dirt out. But Dust and Sand may still be going in. Again: No plug but a grille...

You have put the grille in the existing ridge, with a careful dosage of force.