It's split bushing converters for multiple purposes of chuck or collet sutability. Made of carbide, high strength and hardness.Processing by heat treatment and precise grinding, to use. Used for chuck conversion of trimming, engraving machines. Suitable for engraving machine, wood router.A perfect woodworking tool. Collet Chuck Adapter only, other accessories demo in the picture is not included. Specification: Chuck Size: 8mm, 6.35mm, 6mm (0.31inch, 0.25inch, 0.24inch) Colour:Black + Silver Material:Steel Package Contents: 3 * Collet Chuck Adapter Engraving Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.