This version of the FS5103B standard servo from FEETECH is specially modified to provide access to the feedback potentiometer through a fourth (green) wire, allowing you to directly measure the position of the output. This extra information enables more complex robotics applications, such as determining when the servo has reached its target, detecting when the output is blocked, or implementing your own higher-level closed-loop position control.

Key specs at 6 V: 0.13 sec/60°, 45 oz-in (3.2 kg-cm), 43 g.