Zinc plated. Exact reproduction of the OEM 5983W spacers. Dimensions: 5/8" (15.9mm) OD x 5/16" (7.9mm) ID x 7/8" (22mm) thick. As used behind the Wagner Lockheed type rear master cylinder on early Shovelheads with brake discs. Works in many custom applications as well. OEM replacement reference 5983W
