BABOLAT B281027:SET RPM 17G + VS 16G Tennis String Babolat RPM Blast 17 / VS Gut 16 Hybrid Strings combines the best of Babolat's flagship strings into one package. Gauge: 17 (RPM Blast) / 16 (VS Gut) Diameter: 1.25 mm (RPM Blast) / 1.30 mm (VS Gut) Composition: Monofilament (RPM Blast) / Natural Gut (VS Gut) Shape: Octagonal (RPM Blast)