Made of high-quality materials, practical . Portable size, easy to use and carry. Great workmanship, with strict quality control and quality assurance, high safety factor, can be used with peace of mind. Used for chuck conversion of trimming, engraving machines Screw Nut Size: M15x1 Hole Diameter: 6mm / 8mm / 6.35mm(1/4inch) Note: Installation guide not included, we strongly recommend you seek professional installation. Please check as much as possible to make sure the item is what you need. Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Colour:Photo Color Material:steel Package Contents: 1 x M15 Screw Nut 3 x Router Bit Collet Chuck(6/6.35/8mm) Only the above package content, other products are not included. Note: Light reflection 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.