Spring RC SM-S4315M 2BB Metal Gear High Torque Servo Torque: 4.8V: (180.54oz/in ) | 6.0V: (209.7oz/in) Speed: 0.21sec (4.8V) | 0.17sec (6.0V) Operating Voltage: 4.8 - 6.0V Weight: 61g (2.15oz) Dimensions: 1.63 in (41.3mm) x 0.81 in (20.7mm) x 1.57 in (40mm)