Meguiarâ s 5" Soft Buff DA Backing Plate is designed to distribute pressure evenly for optimum defect removal and finishing. The outer edges are precisely tuned for disc contouring over flat and curved surfaces. Meguiar's DA Backing Plate also features a rotation indicator marking that allows you to recognize backing plate rotation for ideal results. Disc changes are quick and easy with a micro hook and loop attachment system. Can be used with DA polishers with a 5/16" diameter shaft. For optimal results use with Meguiar's Dual Action Polisher MT300 and Meguiar's 5" Soft Buff Foam Discs or Meguiar's 5" Microfiber Discs.