This 4" sheath shows a 4" blade. This is an interference fit, and not only is the case bore the same size as the pot wheel/vane, the blade protrudes 1/4 inch from the face of the case. Rice is a flat, flush-cut blade that interferes with the edges of the casing as well as some of the potted parts within the casing. I doubt you can use this even with a 4 inch cup washer. The brushes do not touch the floor. Haven't used it yet but since it's non-refundable I'll try and update. Don't expect it to work. .