"reactive resin" bowling balls are urethane as far as I know.. They just incorporate plasticizers during the manufacturing to create small voids in the coverstock to make the ball more porous and soak up oil and hook more.
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16-17 mph,350 rpm,PAP 5 1/2 x 3/8up, HighGame 300 x 3, High Series 782
Book Average 215 / 205,PBA Xperience ave180