Yasaka, using mainly natural rubber gum for the top sheet. This improves the level of grip and the power of spin drastically. The top sheet is combined with the new Power Sponge. The top sheet and Power Sponge work in perfect synergy, producing the Hybrid Energy rubber Rakza 7. When the player hits the ball hard, the rubber grips the ball and the stroke can be used to place the ball accurately, both in direction and length. The serve and short returns are very sharp and easy to handle. Due to the increased percentage of natural gum the durability is improved. A winning combination!