Qsmily&reg; Rechargeable 4.8V 400mAh AA 4 In 1 Ni-Cd Battery Set for Huanqi HQ 508 550 611 605 RC Tank RC Car Specially designed to provide power for HQ 508 550 611 605 rc tank rc car. High quality and durable in use. High capacity, enjoying much longer action time. Easy to install.