I work in retirement in a Stainless sheet metal shop and have access to all sorts of off-cuts, I also have creative imagination of what things could be used for, this filter was a flat piece of perf about to be scrapped, I rolled it and stuck a base on it, voila a filter? My thoughts were just to rest it in the FV neck, let it drain , pitch the yeast and screw the top on with the airlock.