STIGA MANTRA S. The STIGA Mantra is developed with the latest Japanese rubber technology and offers the perfect balance of synthetic and natural rubber. This new rubber mixture creates a tension between the surface and the sponge resulting in an incredible catapult effect. Microscopic air bubbles in the sponge (Oxygen Capsule System) provide great speed with a stable and consistent hit and touch. This rubber is perfect for players who require the highest in rubber quality and performance. The SOFT sponge creates a high spin rubber with excellent feel and tremendous feeling, as well as offering exceptional control in service returns.