Sharpening Strap, also known as a STROP, is a leather belt or strap used to sharpen knives, razors, and other cutting tools. It is usually made of leather, canvas, or linen and is used in combination with a sharpening compound to create a smooth, sharp edge on the blade. The leather or canvas provides a surface for the compound to adhere to, while the strap itself helps to evenly distribute the compound across the blade.