These handy pads are for use with the AWP-158, the AWP-214, and the AIR-658. They can also be used with any machine that utilizes a 5/8"-11 spindle (M14 metric spindle). They come in two varieties: a hard rubberized material backer for use with edges, curves and angles; and a hard plastic backer for use with flat surfaces. The face of the backer pad is covered with male velcro which makes them perfect for use with 3M Hook and Loop diamond disks, small smoothing disks, and felt polishing disks.