Angle constancy is the most critical and the most elusive element of hand sharpening – and the Lansky Controlled-Angle System ensures that your knife edge sharpens to the exact bevel you specify. Designed to give your blade a professional, razor sharp edge every time, regardless of your sharpening ability. Excellent for beginners and advanced users alike. The original and legendary Controlled-Angle System is the ultimate in Knife Sharpening technology. The Lansky Controlled-Angle Sharpening Systems allow the user to select the sharpening angles that are best suited for their knife’s intended use. The four sharpening angles and their uses are listed below: 17° Angle – A severe angle recommended for razor blades, fillet knives or similar tools. An extremely sharp but delicate edge. 20° Angle – A commonly used angle for higher quality blades and provides an excellent edge for kitchen cutlery and slicing knives. 25° Angle – The recommended angle for most knives that need a durable, sharp edge. Ideal for hunting and outdoor knives. 30° Angle – An outstanding angle for knives that cut cardboard, rope or carpets. Best for heavy duty use.