Bought this diamond block after seeing an ad from Rob Cosman. Initially the block was very aggressive but after 3 knives of the cutter bar it stopped cutting material on both the 300 and 1000 sides. There are no more diamonds and there is nothing left to shoot stuff with! And that with the use of a special liquid. Thrown over $150 in Rob Cosman ads!1. The board is not level (after the stone is aligned with the diamond, it is not checked in level with a measuring ruler). The diamonds are gone and now this plate can be thrown away. Do not believe what the manufacturer writes and says about Rob Kosman. Everything is clear with the manufacturer, Rob is on the dark side. Made in China, Chinese quality. Money thrown away! Terribly disappointed.