Yasaka developed Rakza 7 using mainly natural rubber gum for the top
sheet. This improves the level of grip and the amount of spin
drastically. The top sheet is combined with the new Power Sponge,
working in synergy, producing Yasaka's newest Hybrid Energy rubber.
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. Serve and short returns are very sharp and easy to control. Due
to the increased percentage of natural gum the durability is improved. A