We have 2", 3", 4", 5" holder backer pads to fit diamond polishing pads of same sizes. Two types of back holders are available - Rigid or Semi-Rigid. Rigid type works better on flat surface polishing while Semi-Rigid holders are better for curved areas. The back holders have 5/8-11or M14 fitting to fit on standard grinders and polishers. They are all velcro backed.