Feature: 1. 9PCS SET: Comes with 9pcs router collet adapter in different sizes, this set will surely satisfy your various working needs. 2. FIRM CLAMPING: These router chuck not only ensures firm clamping, but also enables high accuracy and stable holding. 3. PRACTICAL USE: Used for chuck conversion of CNC machine tools, suits for drill tools and chucks with different features. 4. CARBON STEEL: Forged with premium carbon steel material, which has high flexibility and good wear resistance as well. 5. GOOD DURABILITY: Processed by heat treatment and accuracy grinding, not easy to deform, durable for long term use. Specification: Item Type: Router Collet Adapter Product Material: Carbon Steel Product Colour: Black Inner Diameter x Outer Diameter x Height: Approx. 6.35 x 12.7 x 28mm / 0.3 x 0.5 x 1.1in 8 x 12 x 28mm / 0.3 x 0.5 x 1.1in 6 x 12.7 x 28mm / 0.2 x 0.5 x 1.1in 6 x 12 x 28mm / 0.2 x 0.5 x 1.1in 6.35 x 9.5 x 30mm / 0.3 x 0.4 x 1.2in 10 x 12 x 27.5mm / 0.4 x 0.5 x 1.1in 8 x 10 x 25mm / 0.3 x 0.4 x 1in 6 x 8 x 25mm / 0.2 x 0.3 x 1in 6.35 x 8 x 25mm / 0.3 x 0.3 x 1in Function: Can be used to clamp drill tools, boring tools, engraving machine, reamer, etc. . Package List: 9 x Router Collet Adapter Note: Please clamp the cutter head when using it, and work only after it is firm and stable.