The Precision Brand® Steel Arbor Shim Assortment Kits are used for fast, accurate spacing of milling cutters, gang cutters, saws, slitting blades, and grinding tools. It is Made of high quality, low carbon, cold rolled, full hard, steel shim. Arbor shims have no keyways. It Saves time over re-machining. It has precision thicknesses for more accurate results. Plastic compartment box is easy to store. Assortment kit contains the most commonly used arbor shims.