Lockable gas spring (also called blocked gas spring) can be locked at any intermediate position of the stroke. It has a valve assembly internally, when one operates (presses) the actuator pin, it opens the valve simultaneously applies force on body then the piston rod starts going in & at a moment when force applied on actuator pin removed the valve gets closed which in turn stops the movement of the piston rod. It mainly include three types. 1) Flexible Good resistance to rod being pushed o日 pulled 2)Rigid in tension Rigid when rod is being pulled, high resistance to rod being pushed 3)Rigid in compression High resistance to rod being pulled, rigid when rod is being pushed Applications: it is mainly used where tilting is required. It is mainly used in seat application. The seats of luxury coaches are equipped with the gas springs. Tilting of these seats gives comfort to the passenger & reduces his fatigue during travelling. These are also used in office chairs for back rest tilting & continuous rocking of back rest. Lockable gas spring is also used in patient care equipment such as hospital beds, operation table, bedside trolley etc.