When the valve is opened, the extension force aids the user in adjusting his or her application in that the gas strut bears a large part of the weight force. When the valve is closed, the pneumatic spring locks, thus locking the application in the desired position. Depending on the design, the locking can be elastic or rigid. With the help of the elastic locking, the lockable pneumatic spring responds in a spring-loaded manner in the push and pull direction, since this is only filled with nitrogen.
With rigid locking, the locking gas strut reacts rigidly in the push and pull direction. This is achieved by a defined oil chamber in which the piston moves. The locking force in the pushing or pulling direction is maximized depending on the arrangement of the chamber.