Each setup block has a different thick-ness, It comes with 7 precision setup blocks that can be combined to easily achieve different measurements. Set the height of your fence, blades, bits and other cutters in a fraction of the time. 4 in 1 Design-The woodworking Setup Bars can be used as a height gauge, depth gauge, square stacking gauge and an angle gauge. It is a combination of traditional depth and height gauges and traditional building blocks. Incredible Precision Gauge Block Set.Whether you're measaure your table saw blade or router, you will obtain high-precision measurement values. Router Table Set Up Bars are precise to ± 0.001-0.004inch. Solid Durability Gauge Bars.Solid aluminum alloy material and anodized with a smooth finish can better protect your hands, router bits and table saw. Have a long service life.