The DMT 8 in DuoSharp Plus is a double-sided diamond bench stone in coarse/extra-coarse, fine/coarse or extra-fine/fine, and we also sell the DuoBase that holds it.
Each side has a 6 x 2-5/8 in interrupted diamond section, DMT's polka-dot pattern, for knives and longer edges, plus a separate continuous section for small and pointed tools. The stone is 8 x 2-5/8 in and 3/8 in thick. Sharpen dry or with water; no oil is needed. It comes with a non-skid mat.
The DuoBase is a polymer base for any DuoSharp bench stone, 8 or 10 in, or any 6 x 2 in stone. It gives 2 in of knuckle clearance, rubber feet hold it to the bench, and a handle underneath lets you move the stone over a large workpiece.
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.