This block is designed to allow the user to accurately block panels with slight curves. This innovative Non cloth hook and eye Ultra Flex Series is designed to accomodate a wide variety of paper and allows the user to accurately block panels with slight curves. Features. 11 Ultra Flex PSA Sanding Block. Uses PSA paper. Extra flexibility. The Perfect Blocking Tool. Designed to accurately block slightly curved or flat panels on any car without digging into fill material. Durable, high density EVA foam block follows contours or flats. No dents. No ripples. Wet or Dry Sanding. Dura Block give you the flat, the curve and the edge in sandingSpecifications. Color Black. Size 11. Dimension 13 mm x 67 mm x 280 mm. Weight 3.75 lbs