Arkansas Sharpeners Hard Whetstone AC13. This Knife Sharpener from the good people at Arkansas Sharpeners measures 4" x 2" x 1/2" and comes mounted on a wooden block. Don't let any one know you have a knife without the Arkansas Sharpeners Hard Whetstone. Features of Arkansas Sharpeners Hard Whetstone Knife Sharpener: Arkansas Whetstone Black Hard Measures 4" x 2" x 1/2" Mounted on wooden block Package Contents: Arkansas Sharpeners Hard Whetstone Arkansas Sharpeners AC13: Hard Whetstone