1, gas spring , gas support(reverse gas lift ) 2, Applicable to the tilt-up wooden door and aluminum door and other furnitures gas spring , gas support (reverse gas lift ) , ... your door's weight .Code : ES10211, Gas source : air/nitrogen2, Reverse load : 50N-200N3, Lift distance : 90mm4, Material : Coopper/ damper ... : 100pcs /box 9, Whole amortizing/2-force technology Reverse gas spring and gas lift