High-quality carbide material provides excellent flexibility and wear resistance. High precision with tight and stable clamping performance. Made of carbide, processed through heat treatment and precision grinding for durability. Suitable for use with engraving machines and compatible with various bit tools and chucks. Offers good elasticity and abrasion resistance. Features high clamping force and reliable grip stability. Specifications: Material: Carbide 6.35mm to 12.7mm: Inner diameter: 6.35mm / 0.25 inch Outer diameter: 12.7mm / 0.49 inch 6mm to 12.7mm: Inner diameter: 6mm / 0.23 inch Outer diameter: 12.7mm / 0.49 inch 8mm to 12.7mm: Inner diameter: 8mm / 0.31 inch Outer diameter: 12.7mm / 0.49 inch 10mm to 12.7mm: Inner diameter: 10mm / 0.39 inch Outer diameter: 12.7mm / 0.49 inch 10mm to 12mm: Inner diameter: 10mm / 0.39 inch Outer diameter: 12mm / 0.47 inch 8mm to 12mm: Inner diameter: 8mm / 0.31 inch Outer diameter: 12mm / 0.47 inch 6.35mm to 12mm: Inner diameter: 6.35mm / 0.25 inch Outer diameter: 12mm / 0.47 inch 6mm to 12mm: Inner diameter: 6mm / 0.23 inch Outer diameter: 12mm / 0.47 inch 6.35mm to 9.5mm: Inner diameter: 6.35mm / 0.25 inch Outer diameter: 9.5mm / 0.37 inch 6.35mm to 8mm: Inner diameter: 6.35mm / 0.25 inch Outer diameter: 8mm / 0.31 inch Package Includes: 1 Piece Router Bit Chuck Adaptor (4 Pack)