The Scotty Knife Sharpener #990 is the ultimate blade sharpening device! Simply hold the sharpener in one hand and draw your knife through the sharpening blades. The result is a razor sharp knife blade in seconds! So handy you will want one for your tackle box, galley, barbeque and workshop. Tungsten carbide blades may be rotated to 8 different positions to extend the life of the sharpener.