The Karakal BX 130 Gel Squash Racquet is Karakal's most popular frame with an inner 'Muscle System'. The 'Muscle Tec' string system allows the strings to move freely over rounded raised grommets enabling it to be strung at a lower tension yet gives a high tension feel and therefore increases the size of the sweet spot. Frame Weight: 130g. Head Size: 470 cm sq.