In this Auto LIFT type, damping is provided during opening / extension of the gas spring. Just before the gas spring completely extends, the speed of opening slows to avoid impact at the end. This is the most commonly used type of gas spring where ever a simple opening of lids, doors, luggage compartments, etc. is needed.
In this type, damping is provided during closing / compression of the gas spring. The damping is provided to avoid impact during closing of the application. For example, to avoid slamming of a door on the door frame while it is closing. In this type, the closing effort required near the compressed condition is more due to damping provided.
This is a combination gas spring of the first two types, i.e. Damping in Extension & Damping in Compression. The applications of this type are unique, e.g., opening and closing of doors in highly windy conditions at high altitudes, where damping is required simply to oppose the wind force in either direction, while opening or closing.