For your consideration, here is an Enerpac Hydraulic Tool Rule Calculator Wheel. It has a date of 1961 on it. It has printed on it A Blackhawk Industrial Products Company. It has a diameter of 6 1/2 inches. The wheel has wear on the edges and a creases in one edge. Item pictured is the actual item up for sale and comes from a non-smoking household. (69.830m-.4ob)