High PrecisionThe thickness of each of the blocks is machined to within 0.001" accuracy. More than accurate enough for your woodworking and joinery needs. Durable & SolidThese solid aluminum alloy setup blocks with black anodized finish prevent router bits and saws from damage Aluminum alloy featured with lowdensity, and close to even exceed premium steel in strength. So it is lighter, durable, inflexible and corrosion resistant, enough to withstand many uses without wearing out. Engraved size markings are easy to read and last life Besides these setup bars come in a handy storage case keeping them in organized and quick to access. They make setting up process easy, faster and more accurate than using a combined ruler, especially when you need to change heights and distance constantly. Various Sizes There are 15 pieces various sizes gauge blocks: 1/16", 3/32", 1/8", 5/32", 3/16", 7/32", 1/4", 5/16", 3/8", 7/16", 15/32", 1/2", 23/32", 3/4", 1x2x3". Set up gauge blocks are all 3 inches long. Each block with good flatness, you can stack setup bars for additional sizes you need except use on their own. Versatile BlocksThey are great for set the height and distance of the fence, blades and bits on your table saw, router and other cutters according to your needs. This gauge block set is a nice addition in your home workshops - for woodworking, metalworking, etc., Manufacturer: SOYWIM