Apacs Lethal 10 Badminton Racket (4u) Isomectric head frame - Equalizes the length of main and cross strings in the stringbed, enlarging the sweet-spot for more consistent accuracy even on off-center hits. Hi-Tension Frame - With the Hi-Tension Frame the maximum Horizontal String tension is 38lbs and Vertical string tension is 36lbs. The strengthened frame is more stable thus enabling more control and performance during smash and fast drive. CNT Carbon Nanotube - It holds large amount of energy at the impact, and releases it back like an arrow. It gives you depth and control in your game. The strength and flexibility of CNT Carbon Nanotube will lead your game into the next level. High Speed Frame - The High Speed Frame design is an aerodynamic shape frame designed to reduce drag on the frame during straight on swing or hit. Resulting in a fast swing-through and the quicker maneuverability.