Bona Steel Plates are designed to be used with the Bona Flexisand 1.9 sanding machine. If you're looking for the flattest possible sanding system, the Bona Steel Plates are just what you need. Reducing the chance of any dish-out on final sanding and removing chatter marks, these are the ideal solution for creating the flattest floor possible. 4 x 150mm diameter. Can be used with both standard and NEB Power Drive Plates.