2 PACK HS-645MG Hitec Ultra Torque Servo High quality and high performance at a great price Speed: 0.24sec/60 at 4.8Volt Torque: 7.7kg.cm(107oz.in) at 4.8Volt Weight: 55.2g(1.9oz) Size: 41 X 20 X 38mm (1.59 X 0.77 X 1.48)"