These mechanical linear actuators are preassembled and ready to use. They include an adjustable gearbox that can be positioned at every 90 degrees. Synchro-use actuators connect at the linkage shaft to be used in pairs. The synched carriages on the two units move along with the rotation of the single shaft. They can be used with simple manual adjustments without complex processes of parts selection, design and assembly. Internal parts are protected from dust by an aluminum profile body and dustproof sheet. The body is made from A6N01 aluminum. End plates are made from chrome-plated die cast zinc. The shaft is made from 1045 steel with a black oxide finish. The gearbox is made from 1045 steel, electroless nickel-plated.