Dura-Gold Pro Series Classic Rectangle Hand Sanding Block Kit with 3 Blocks, 5", 7-3/4" and 10" Set, Hook & Loop Backing and PSA Sandpaper Adapter PadDura Gold Pro Series Classic Rectangle Hand Sanding Block Kit with 3 Lengths of Sanding Blocks; Sizes 5", 7 3 4" and 10" long x 2 3 4" wide. Uniquely designed rectangle hook & loop hand sanding blocks with a 2 way design system that allows them to be used with both hook & loop and PSA sandpaper sheets. Each block includes an attachable PSA conversion adapter pad with a vinyl face that converts the blocks for use with PSA pressure sensitive adhesive