Norton 100mm Round Combination Stone XJB74
With two grits back-to-back on the one stone. In silicon carbide as a sharpening stone and for ferrous materials above Rc35, and aluminium oxide which is a little less aggressive providing a smooth finish and for stainless steel and materials below Rc35. (Closely resembles the "India Stone").
Material: Silicon Carbide
Size: 4" dia x 1½"