... 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 ... 4 5. SGS BIFMA X5.1(100, 000 Times Testing) 6.Pressure(N): 300--450 7.Bottom Color: White,Black,Orange ... ,Green 8. Warranty: 5 years 9. OEM Service10.ISO9001 Certificate. gas spring or gas cylinder for a variety of chairs