Tenergy FX produces a high level of control without losing high performance. Tenergy 05 FX combines High Tension technology with a version of Spring Sponge that produces a softer feeling. It is a result of extensive research, the name deriving from Code 05, being one of many experiments carried out by the Butterfly Research Centre. Tenergy 05 FX is the perfect answer for players who seek to play heavy topspin strokes, whilst maintaining control.