Yonex S-FIT 1 Tennis Racquet IMPACTSPEED Positioned on the sides of the frame, CS Carbon Nanotube gernerates additional power with every swing and increases ball dwell time, holding the ball on the strings longer for shots with more finesse and directional accuracy. New Innovative Select Fit System You can tune your racquet whichever way you want, whatever the temperature, surface or condition of your match. DUAL O.P.S. Effortless Power The S-FIT Series feautures Innovative Dual O.P.S. (Oval Pressed Shaft) where the split shaft provides 10% less vibration, 10% less air resistance and 13% more stability.