Blade sharpeners are tools used to sharpen blades, such as knives, scissors, and razors. There are two common types of blade sharpeners: strops and whetters. Strops are leather or canvas strips that are used to sharpen blades by rubbing them against the strip. Whetters are stones or metal plates that are used to sharpen blades by grinding them against the surface. Both strops and whetters are effective in sharpening blades, but the type of blade sharpener used depends on the type of blade being sharpened.