Yasaka Rakza 7 is now ranked as our best selling rubber, it is manufactured by using mainly natural rubber gum for the top sheet. It improves the level of grip and the power and spin drastically. The top sheet is combined with the new Power Sponge. Top sheet and Power Sponge work in perfect synergy, producing the Hybrid Energy rubber Rakza 7. A winning table tennis combination! Rakza rubbers use Hybrid Energy to provide synergy between top sheet and sponge providing great elasticity for power and control.