A strop is a surface that is used after the finest stone for the final stage of sharpening. The function of a strop is to polish the edge and work off any burr left behind by sharpening stones. Although other materials are used such as Balsa wood, Nano Cloth and Denim, strops are generally made of leather. Both the suede and smooth sides of the leather can be used. They can be mounted to a rigid base, like leather on a wood paddle strop, or can be flexible like leather or a linen razor strops traditionally used by barbers.