Click to expand Tap to zoom Helix Rubber Backers by Helix Sale $15.71 | / SKU BPR412 4" Rigid - $15.71 4" Flexible - $17.14 4" Rigid 4" Flexible Size 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Helix rubber backer pads. Durable design features hook and loop back for attaching diamond polishing pads, sandpaper or felt wheels. Fits on polishers and variable speed grinders with 5/8"-11 threaded arbor.