Made of hard alloy, durable and convenient to use. Suitable for automotive manufacturing, mold making, machine making, etc. Eliminate the dangerous temptation to remove the shank from the collet, lengthen the bit to get the full depth of cut. The extension rod should be tight, but the clamp nut should only be tightened with the same pressure as any router clamp. This clamp extender allows you to change router bits above the table, even without a lift. Even if you have an elevator, they still make bit changes easier as you won't have to remove the insert ring. They are also great for custom routing tables with extra thick tops, as they provide the extra depth of cut needed for many routing tasks. Features high precision, stable performance, high resistance and hardness, durable in use, making processing more efficient. Specifications: Material: Hard Alloy; Color: as shown; Shank diameter: 8mm; Keep diameter: 8mm; Total length: 86mm; Content: 8mm Router Collet Extension.