In order to choose an exact replacement vent cover for a trailer roof vent you'll want to pull the model number off the inside of the frame under the screen. If you cannot obtain this we do offer universal covers like the MaxxAir UniMaxx Universal Replacement Lid for RV and Trailer Roof Vent part # MA00-335001 for white or part # MA00-335002 for black that should still work well. view full answer...