ECO-WORTHY 12 Volt 18 Inch Stroke Linear Actuator 330 Pounds Lbs Maximum Lift for Solar Tracker Retracted length = 23.62 inches (600mm), Stroke length = 18 inches (450mm), Maximum current draw = 5 Amps, Maximum Load = 330lbs(1500N) Unit can be controlled with a double pole, double throw switch or with the built-in position sensor and optional linear actuator programmable controller. 12V motor has gearbox and is rated to hold up to 330 lbs when not moving. An all-metal housing and is water-resistant and sealed against dust for rugged durability. Quiet clean and energy efficient operation. Accurately positions the load at variable and repeatable locations within the full stroke. Package included: 1 piece 12V 18" stroke Linear Actuator with 2pcs mounting brackets. Input Voltage: 12VDC Stroke Length: 18&#034;/450mm Retracted length:24&#034;/600mm Extended Length: 42&#034;/1050mm Max Push Load: 1500N/330lbs Max Pull Load: 1000N/264lbs Maximum Load: 1500N/330lbs Travel Speed Without Load: 0.22in/sec (5.7 mm/s) Duty Cycle: 25% No-load current: 0.8A Max load current: 3A Protection Class: IP54 Rated Color: Silver The linear actuators are controlled by applying a 12VDC voltage.Basically, connect the two wires to a 12 volt battery. For 2pcs actuators, please wire them IN PARALLEL, then connect the wires to 12 volts battery. Reversing the polarity will make the actuator reverse. Red wire to the positive terminal and black wire to negative terminal will make it extend. To make it retract, reverse the terminal connections. The actuator has pre-installed limit switche inside,it cannot be adjustable. It will hold its position when the power is off. It will auto stop when it reaches the end. L<span class="a-text-bold">inear actuator</span>is anactuatorthat creates motion in a straight line, in contrast to the circular motion of a conventionalelectric motor. Linear actuators are used in machine tools and industrial machinery, in computer peripherals such as disk drives and printers, in valves and dampers, and in many other places where linear motion is required. Hydraulic or pneumatic cylinders inherently produce linear motion. Many other mechanisms are used to generate linear motion from a rotating motor.