Flexible Rubber backer pad    These tools are made of rubber materials, used for dry or wet polishing. Most flexible. The back is hook of velcro, they can attached with the polishing pad easily. They are used for maintain and renewing the stone and other item.    Rubber backer pads are perfect for corners or other curved areas. Most flexible and allow the operator to finish these areas with ease.    Velcro backed flexible rubber discs for attaching polishing pads to hand-held electric polishing tools.  Plate Disc intended for attaching dry or wet polishing pads.Available sizes:3", 4", 5", 7", two kinds of threads, other sizes are upon requested. 7"flexible backer pad is used for polishing irregular surfaces. High performance and good quality. Thread :  5/8-11,M14