Hemispherical Reducer with Filter Plate V3Hemispherical Reducer with Filter Plate V3 This hemispherical reducer has a built in filter plate that is welded flush with the top of the reducer. This unique design allows the user to save even more space by combining a filter plate and hemispherical reducer. Made out of 304 stainless steel the filter plate is welded into the hemispherical reducer and has Tri Clamp connections on both ends.