For sale is a lot of TWO, HUGE EDM Graphite Blocks. They are both marked KK-10 and are 12x12x1 3/4, and 10x12x2 inches. (one is 12x12 1 3/4 inch thick and another, is 12x10 and 2 inch thick). Both have one corner removed, as you can see, No holes drilled on the blocks. I think that they are raw materials and were used only to cut out blocks from them. I have no idea what is KK-10.