... SGS test 2.100000 times fatigue test 3.Surface:Black,Chrome 4.free sample 1.Gas Lift,Gas Spring ,Gas Cylinder ... ,Gas Strut for Office Chair,Bar Stool,Table 2. Stroke(mm): 80,100,120,140,160 ... ,230,260,3303. Surface: Black,Chrome 4. Standard: Class 2,Class3,Class 4 5. SGS BIFMA ... Certificate. gas spring or gas cylinder for Office Chair and bar chair