Tenergy 3.6V 2000mAh Side-by-Side Ready to Use NiMH Battery Packs w/ BEC Connector for RC airplanes, Walking robot etc. made of 3x AA NiMH 2000mah cells Fit Models: RC airplane: Hitec, Futaba and JR etc Walking robot. Dimensions: 52mm (Long); 42mm (Height); 15mm (Thickness) Rapidly charge up and long cycle life Connector:with universal radio connector, solid welding with 22AWG silicone wire