Spyderco Ceramic Benchstones, Medium

The Spyderco 302 ceramic sharpening stone medium, 302M is a top-quality ceramic stone made from aluminium oxide (synthetic sapphire) to sharpen knives and other tools. The advantage of aluminium oxide is that you don’t need water or oil and that it is so hard that even after a long time sharpening grooves won’t appear. You can also easily sharpen hard metals with this stone.