Universal Entrance Reducer. The best entrance reducer, you will step on it and break it before it breaks down in the weather. I'm still using our orginial ones from 2015. Ours are made out of Douglas fir, and are weatherproofed by boiling them in a solution of paraffin and tree rosin like our bottom boards for years of use. These wedge shaped entrance reducers are ready to use and will fit any size bottom board, regardless of the size opening.
Remember to store them out of the dirt. Weatherproofing Douglas fir does not deter termites.