Strong and Durable: Dynamically balanced and made of fatigue-resistant steel, the short length and solid body prevent distraction in other extensions Easy to Use and Convenient: Quickly change router bits from above the table with one wrench, no need to fumble for your spindle lock or use a pair of wrenches to change bits again Router Collet Extension for 1/4 Inch Bits, 1/2 Inch Bits, 8mm Shank Bits; Need to tighten with a wrench to prevent the bit from falling off. Make you more efficient to process products, suitable for woodworking trimming, milling, engraving machine. Package Including: 1 x 1/4 Inch Router Collet Extension, 1 x 1/2 Inch Router Collet Extension, 1 x 8mm Router Collet Extension. Note: The data are all measured manually, please allow 1-3cm error Due to differences in light and display, there may be some color differences, please refer to the actual item received.