Each of these six Dura-Block® Sanding Blocks are made of closed-cell EVA rubber for just the right amount of sturdiness and “give”, and come in a wide range of shapes and sizes to help you level all types of flat and contoured surfaces. Use for both wet and dry sanding. We recommend you get our adhesive-backed sandpaper (PSA), whether individual sheets or continuous roll, to use with our Dura-Block® Sanding Blocks. AF4400 Standard Block 3/4"H x 1-3/8"W x 11"L This block is designed to follow contours or flats. No dents, no ripples. AF4401 1/3 Block 1-1/2"H x 2-5/8"W x 5-1/2"L This block is designed to follow slightly curved or flat panels without digging into fill material. AF4402 2/3 Block 1-3/8"H x 2-5/8"W x 11"L This block is designed to allow the user to accurately block flat panels and panels with slight curves. AF4403 Full Size Block 1-3/8"H x 2-5/8"W x 16"L A favorite among the professionals when blocking large surfaces. AF4404 Round Block 11"L x 1-1/4" Thick This is the "Round" style block. Use to sand and block highly curved surfaces. AF4405 Scruff Block 1/2"H x 2-1/2"W x 5-3/8"L