This is the first rubber to feature Butterfly’s new “Spring Sponge”. Spring Sponge feels hard yet its new technology allows it to hold the ball on the racket longer. Tenergy 05 combines this new explosive sponge with a new tensioned top-sheet with maximum surface grip. The result is a rubber that produces massive amounts of spin on serves and topspin drives. Tenergy is also one of the fastest most explosive rubbers in our line all without the use of any speed-glues or tuning. Tenergy will keep its speed throughout the life of the rubber without need for any special treatments.