**White Sponge (37-38°):** Optimized for “transparency” and feedback. It offers a slightly softer feel, making it easier to “sink” the ball into the sponge for incredible control and a higher success rate on opening loops.
* **Blue Sponge (38-39°):** Engineered for the power-hitter. The Blue Sponge provides a denser energy reservoir, resulting in a stronger second-speed acceleration and a more aggressive “arc” that is difficult for opponents to time.

Both variants utilize 729’s latest high-elasticity technology, ensuring that the rubber feels “alive” even without professional boosters. It is a stable, high-fidelity tool that rewards technical aggression with professional-grade velocity and legendary spin.