Waveshare 25127 20kg.Cm 106PRM High Speed Bus Servo Motor(ST3215-HS)1. The servo motor can feedback a variety of information: position, speed, torque lock, operation mode (servo mode, servo motor mode, etc.), which can be used for high level projects that require closed loop automatic control 2. It can be used to build wheeled robots, 3D printers, etc. that require accurate closed loop speed control or stepping control; it can also be used to build robot projects that require multiple servo motors, such as quadrupeds,