Poly-X Core Blue Stitch Color Official Ball of USSSA Yellow ProTac synthetic leather for increased durability Hot Dot polyurethane maintains compression in hot weather These 12" slow pitch softballs have .40 C.O.R. and 325 lbs compression with blue stitching and are approved for play in the USSSA. ?USSSA softballs features a ProTac synthetic leather cover and Worth Hot Dot softball technology is designed to give players consistent hit distance at all temperatures, especially in hot weather conditions.