Spalding PRO Series NFHS Premium Leather Baseballs Improved Grip And Accuracy Spalding PRO Series NFHS baseballs feature a premium full grain leather cover with a cushion cork center plus a raised seam for improved grip and accuracy. A Spalding PRO Series NFHS Premium Leather Baseballs feature: Premium Full-grain leather cover Cushioned cork center Spalding raised seams for improved grip Spalding raised seam is 30% higher than a traditional flat seam ball.