In addition to force support, the LIFT-O-MAT gas spring with end position stop also provides a safe mechanical lock of the application in the extended position. As a rule, two variations are available: In the gas spring with the stop on the outside, a support tube at the end of the piston rod folds out automatically. To unlock, the support tube is swivelled back into the central position. The lock of a gas spring with the lock on the inside is comparable with the mechanics of a ball point pen. A light push on the piston rod in the extended position locks it; a quick movement in the extension direction releases the lock. A lock is always necessary or recommended, if the application needs to be protected against accidental adjustment or if the application is subject to forces that exceed the extension force of the spring. Such forces could be wind or snow loads affecting the application. Typical areas of application are heavy doors on harvesters or bale presses, trailers for street vendors and street fairs.