It's designed to hold a standard paint filter. The large base is so you can glue it to the lid of any container you want. It is small enough to fit on most jars, but I intended it to fit on an old popcorn bucket. Simply cut out a slightly bigger hole than the funnel has in the bottom (35mm). The raft is purely optional. I used it mainly to get a slightly rougher bottom than I would get from my build plate so the glue would stick better.