The 358 Backing Plate is a velcro grip 3" hd back plate. Primarily designed for the 3" pads. This back plate was made with a heavy duty plastic molding strong enough to indure the high rpm's of a rotary buffer or drill. Designed with a 5/8x11 standard thread it has adaptors to allow it to work pneumatic polishers. So the 358 Backing Plate can fit almost any of your machines. Great for doing headlights and getting in those hard to reach areas.