Rockwell pattern (6 on 8.75) scalloped wheel center to fit 15" wheels. Center is cut from 3/8" steel, 12 1/2" in diameter with chamfered lug nut holes. DISCLAIMER: Not all 15" wheels are the same. The customer must determine if the 12.5" diameter of this center is suitable for their particular wheels and backspace requirements. Contact us for other outside diameters.