Quality size 4 rubber covered, nylon wound ball, with a butyl bladder.We are excited to introduce our NEW HAWAIIAN COLOR MY CLASS174 ultimate color management system. With the ever increasing size of most PE classes, it becomes difficult to keep playgroups to a manageable size. By extending your playgroups from 6 to 12, you can maintain smaller groups ensuring every child has a turn to play. Add the new HAWIIAN set to your original COLOR MY CLASS174 Prism Pack or purchase both to enhance your options. All items come in Blue, Green, Orange, Purple, Red and Yellow with our unique HAWAIIAN design. Only sold as prism packs, which include all 6 colors. This unique and fun design is sure to get the kids146 attention as well as serve as a useful group management system.