Deep Groove Shallow Groove Deep Groove 26mm 22mm 23mm 27" Total length 320mm Balance Martina Hingis Belinda Bencic Nick Kyrgios Ana Ivanovic 24mm 19mm 23mm 27" Total length LG:330mm G:310mm Balance Maria Kirilenko OFF-CENTER CENTER enter hits achieve nearly the same ball speed and repulsion as Centre Off centre Off-centre hits achieve nearly the same ball speed and repulsion as centre hits* OFF-CENTRE HITS Lightweight ISOMETRICTM AERO SHAPE TRANS-WEIGHT SYSTEM O.P.S. DUAL SHUT SYSTEM Super Cushion Grip ISOMETRICTM AERO SHAPE TRANS-WEIGHT SYSTEM O.P.S. DUAL SHUT SYSTEM Super Cushion Grip NEW NEW