Abstract: Identification of work pieces such as wrenches by providing a unique color marking that permits a desired wrench to be selected from a group of wrenches by identifying the unique marking. The marking can be a color code provided by a single band of colored tape affixed to the work piece and unique for each different size of the work piece. In another color coding scheme a different color is assigned to each different digit of the numerical system. Two color bands can then represent a two digit numerator of a functional size and two additional color bands can represent the denominator so that any size from 0 to 98/99 can be indicated.