Miken Chill-10 Composite Fastpitch Softball Bat (2-Piece) Miken's Sensi-Flex maximizes energy transfer from handle to barrel increasing bat head speed through the hitting zone, while eliminating vibration Miken's Tetra-Core technology optimizes performance by utilizing an inner core tube, increasing compression for unmatched responsiveness 100 Comp is the revolutionary formula that changed the game and introduced certified Miken high performance equipment Made in USA