This is the Actuonix L16 Linear Actuator, 50mm, 63:1, 12V w/ Limit Switches.
This unique line of Miniature Linear Actuators enables a new generation of motion-enabled product designs, with capabilities that have never before been combined in a device of this size. These linear actuators are a superior alternative to designing your own push/pull mechanisms.
The L16 actuators are complete, self-contained linear motion devices with end-of-stroke limit switches for simple two-position automation. Simply apply a DC voltage to extend the actuator, and reverse the polarity to retract it. The L16 is designed to push or pull a load along its full stroke length.