Lansky Diamond whetstone extra coarse

Lansky Diamond Sharpening Stone Extra Coarse - for particularly hard knife steels or when you need to work quickly. It can be used with or without oil. If you use oil, please clean the stone regularly to prevent it from clogging. The advantage of oil is that it binds the dust that accumulates relatively quickly on the diamond. Alternatively, water can be used, but it tends to not adhere well to the stones.