Specifications: 1. Material: plastic and metal 2. Full length of flexible drill bit extension: 30CM / 11.81inch. 3.Drive socket set size: 5-13 mm 4. Color: Black 5. Hex shank and outer hexagon dimensions: 0.25inch / 6.35mm. Precautions: 1. Please control the rotation speed. It is suitable for low speed and not fast. 2. Not suitable for electric drills without torque adjustment. 3. Please pay attention to the matching of size before use. The package contains: 2 * Flexible drill bit extension 1 * Drive socket set. There are nine drive sockets of different sizes in the kit. 1 * screwdriver bit set. There are 12 different screwdriver bits in the set.