Dura-Block (Ultra-Flex) Dura-Flex 16" PSA Durablock AF4435Get an professional finish with top of the line sanding blocks from Dura Block. Great for wet or dry sanding, the blocks are made from patented closed cell EVA rubber. They are sized and shaped to create flawlessly flat surfaces and or detailed contours without ripples or gouging. The AF4435: For blocking large panels For use with PSA sandpaper Great for wet or dry sanding Size: 5 8"H X 2 3 4"W X 16"L