[High-quality materials] The chuck of the engraving and cutting machine is made of carbon steel materials, which has good flexibility and wear resistance. [Hole diameter] 6mm/6.35mm/8mm, 3 sizes meet different usage needs. Also supplied with 2 nuts. [Woodworking Tools] The router clamp is suitable for engraving wood milling, automobiles, molds and mechanical engineering. Is the perfect woodworking tool for engraving machine, wood router. [Easy to carry] The cutter chuck is easy to carry, has very precise, tight and stable clamping, and improves work efficiency. [Easy to use] Fine workmanship, stable performance, very easy to use. Features: Hole diameter: 6/6.35/8mm. Quantity: 6pcs (2pcs for each size) +2pcs nuts Material: carbon steel. Height: 3 pieces 20 mm, 2 pieces 8.4 mm, 1 piece 7 mm High resistance and hardness. Easy to use. Sustainable use. The package includes: 2pcs*6mm Clamp adapter. 2pcs * 6.35mm Clamp Adapter. 2pcs*8mm Clamp Adapter. 2pcs*nuts 2-3cm difference exists due to different measurement way, please confirm the detailed size before ordering, thanks for your understanding & cooperation. According to the different monitors and light, please allow a slight color difference.