This backing plate is designed to replace the original backing plate for the Flex XC 3401 VRG. It allows you to use 5 inch and 6 inch pads with your Flex polisher. Designed by Flex specially for this polisher, the 4 3/8 inch backing plate features a “gear-driven” design that delivers a true dual-action motion. The OEM Flex backing plate is designed to reduce vibration while providing even motion and buffing. This backing plate is made of durable molded plastic with a urethane pad to dampen vibration and heat. Hook and loop fasteners cover the bottom of the plate from edge to edge.