Gas strut/shock/spring Identification

[KaHuNaZ]

Guys, Im having trouble finding a gas spring for a project Im working on and I dont know what to search for.
I have a deezee tailgate assist with the gas spring im looking for.

It works the opposite from a typical gas shock and slows the rate of the tailgate falling. I would buy another tailgate assist, but I need one with a little more travel. What is this thing called?

Thanks in advance!

 

[MileHighRover]

Tension gas spring.

 

[larry_g]

https://www.mcmaster.com/gas-springs

At Mcmaster carr