Bosworth Mizuno Pro MS-21 Mizuno Pro MS21 Tour Select Headsize: 100 sq. inches Strung Weight: 14.4 ounces Balance: 5 points head light Swingweight: 398 Stiffness: 46 String Pattern: 16x18 Heavy, flexible and with a high swingweight, the Pro MS 21 is a demanding racquet best suited to advanced players. Foam filled thermoplastic construction drives up the weight, but offers a very comfortable feel.