This set includes 3 pieces of 6.35mm 1/4" to 4mm micro bit hex socket shank and 3 pieces of 1/4" to 4mm drill extension bit holders. The adapters are 25mm in length, and the extension holders are 45mm long, ensuring versatility for various applications Made from high hardness alloy steel, these 1/4 inch to 4mm bit adapter are built to last. Their premium material ensures strength, durability, and resistance to wear, providing reliable performance over time Equipped with magnets, these 1/4 to 4mm hex micro bit socket shank converter securely hold micro bits in place, reducing the chances of bits slipping out, and enhancing overall work efficiency Designed for seamless integration with a 1/4" bit driver, the adapters allow you to easily use micro bits for both manual and electric tools, nice for professionals and DIY enthusiasts alike These adapters facilitate a faster, more organized work process, making them nice for various tasks that require precision. Their design ensures you can work smarter, not harder Product Name: 6-Piece Drill Bit Adapter Material: Alloy Steel Color: Silver Weight: 45g Specifications: 6 pcs Dimensions: 1.77 inches (45 mm) / 0.98 inches (25 mm) Package Contents: 6 PCS Hex Screw Driver Bit Adapter 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.