Damper strut
Damper strut is different from gas springs, there contains no gas inside, only oil or grease, so it is not able to extend or compress automaticly when release force, and can stop as any position.
Dampers are mostly used at rear tailgate as assist and desk to protect people from harm, to resist damage when dropped or knocked. There are two dampers, one is push damper and the other is pull damper.