Lansky Sharpeners Multi-Angle Knife Clamp/Honing Stone Guide Only. The core of each Lansky knife sharpener system is the combination knife clamp/honing stone guide unit. Fully ambidextrous, made of aircraft grade aluminum, the multi-angle knife clamp/honing stone guide has a convenient thumb screw adjustment for secure blade positioning, a mounting hole on both sides (for 360 degree rotation when using a mounting system), and choice of 17, 20, 25, or 30 degree angle settings for the honing stone. The honing stone guide insures an exact stone to blade angle-taking the guesswork out of knife sharpening. The knife clamp/honing stone guide unit is easily utilized by holding it in your hand: optional mounting systems are available-sold separately.