This is a knife sharpener from the leathercraft tool brand nattools. By changing the clamping position, you can easily adjust the sharpening angle. Even beginners can sharpen at the correct angle, improving work efficiency. It is made sturdy and durable. How to use: 1. Loosen the left and right screws and clamp the leather knife. 2. Check the angle you want to sharpen the leather knife to on the body, and extend the specified length. Example: If you want to sharpen to 15°, extend the blade tip 2.3cm. 3. Roll it on the whetstone. #leathercraft #knifesharpening #nattools