These 3rd generation linear servos utilize an improved position sensing system to provide smooth precise movement. This is not a linear actuator, but rather a linear servo. It has an internal sensor that senses current position and a processor that will accept a commanded position and it will move go to the position commanded by an external RC PWM input signal. It will hold that position indefinitely with or without power. This industrial grade linear servo product responds to standard RC PWM control signals from RC radios, Arduino microcontrollers, etc. IP54 environmental rating ensures moisture and dust stays out. Rugged extruded aluminum housing provides low weight and good durability. Several speed, and force levels available. Call or email for more details.