High-precision Sharpening: MR-13B drill bits sharpener excels at sharpening point angle and lip relief angle. It features 11 elastic collets - 3,4,5,6,7,8,9,10,11,12,13, suitable for 3-13 diameter of drill bits. Plus, a professional drill bits collet chuck is included for your safe operation. Adjustable Angle: Our drill bits sharpener provides 95° to 135° point angle adjustment, ensuring precise coordination with drill hole material and rotation speed. Moreover, you can also DIY the lip relief angle through the positioner pins, grinding 4 types of lip relief angle to meet different needs. 2 Grinding Wheels, Easy Replacement: Choose between CBN or SDC grinding wheels for compatibility with various materials. The CBN model is suitable for high-speed steel materials, while the SDC model is used to grind alloy tungsten steel materials