HEAD's junior racquet series helps kids to get started on their exciting tennis journey. Made of an aluminum o-beam construction, the Speed 21 is great for kids just getting into the game who are 4 and older and 40-44 inches in height. Weight (unstrung) 180 g / 6.3 oz String Pattern 16/17 Head size 520 cm² / 81 in² Grip size 000, 0000 Balance 255 mm / 0.5 in HL Length 535 mm / 21 in Beam 20 mm Age 4 - 6 DampPlus The unique DAMPPlus insert isolates impact vibrations from the grip for exceptoinal comfort.