The U specifies the weight of the racquet. The lower the number, the heavier the racquet. 2U, 3U, and 4U racquets are common.
The G specifies the grip size. The higher the number, the smaller the grip size. G3, G4, and G5 racquets are common.
what does 3U/G4 or 4U/G5 mean?, confuse