Mad Catz Z-Chuk Wireless Nunchuk Controller for Nintendo Wii (Black) Mad Catz Wireless Z-Chuk for Nintendo Wii General Features: Black color State-of-the art motion-sensing technology 2.4 GHz wireless technology Built-in rechargable battery Recharges via Wii or PC (USB interface) Fully compatible with all Nintendo Wii Remotes Slip-resistant rubberized analog stick Ergonomic design