DMT Diamond Whetstone Kit DMT7EFC. This Knife Sharpener from the good people at DMT includes fine extra fine and coarse stones that measures 2 5/8" x 7/8". Don't go hiking without the DMT Diamond Whetstone Kit Knife Sharpener. Features of DMT Diamond Whetstone Kit Knife Sharpener: Includes fine extra fine and coarse stones Each stone measures 2 5/8" x 7/8" Hang packaged Package Contents: DMT Diamond Whetstone Kit DMT DMT7EFC: Diamond Whetstone Kit