Butterfly Tenergy 25 FX powered by Spring Sponge Technology and with pimples of a larger diameter than other rubbers, Tenergy 25 creates dynamic attacks for close-to-the-table play. Spring Sponge Technology is produced by the unique format of air bubbles within the sponge and the thin pimples of the highly flexible surface, enable dynamic topspin play with heavy rotation. Butterfly Tenergy 25 FX combines the same top-sheet of Tenergy 25 with a softer sponge layer and is adept at drop-shots, flicks, short pushes and quick counter attacks. Butterfly Tenergy 25 FX is making it perfect for close-to-the table play. Within the Tenergy Family of rubbers, all styles of play can benefit from this new technology.