5-6 Professional Velcro Hook Backing Plate designed to Hook & Loop fast attachment.For use with 5.50 to 6.00 diameter pads that have loop material backing.This backing plate will fit the standard 5/8 thread which most traditional variable speed buffers are equipped.For those of you that have the 5/16 thread, we have included in this kit a DA Pneumatic Adapter.This will allow you to convert the 5 velcro backing plate to fit your style of sander or polisher.Now you can easily apply and remove any 5.5 or 6 diameter foam or wool velcro pad.