The DMT 10 in Dia-Sharp is a continuous-surface diamond bench stone, 10 x 4 in, in coarse, fine or extra-fine, or double-sided fine and extra-fine.
The diamond surface is continuous, with no holes, so small and pointed tools slide across without catching. DMT says it won't hollow or groove. The size suits long and short knives and edge tools, and DMT also recommends it for flattening plane soles, plane irons and chisel backs. Sharpen dry or with water; no oil is needed.
The single-sided stones have non-skid rubber feet. The double-sided stone comes with a non-skid mat.
DMT, short for Diamond Machining Technology, was founded in 1976 by aerospace engineers. It started out making grinding wheels, and its first hand sharpener was made from the center punched out of a diamond grinding wheel. A buyer at L.L. Bean tested an early sample and worked with DMT's engineers to refine it. Acme United bought DMT in 2016, and DMT is based in Marlborough, Massachusetts.