Yonex Voltric Z Force II Badminton Racquet (3U, G4) - Unstrung The Yonex Voltric Z Force II has the thinnest ever shaft and improved TRI-VOLTAGE SYSTEM increases the smash energy. Type: Offensive ; Flex: Extra Stiff Frame: H.M. Graphite, Sound Filter, NANOMETRIC, Tungsten Shaft: H.M. Graphite, EX-HMG, NANOMETRIC Weight: 4U (80-84.9 grams) G5 / 3U (85-89.9 grams) G4