These Official 12″ K-Master fastpitch softballs have .47 C.O.R. and 375 lbs compression with white stitching and covers. These Worth’s ISC softballs have a high density Poly-X cork and SYCO composite leather cover for added durability. �ISC �12 inch �.47 COR �375 Compression �High Density Cork Core �Syco Cover �White