office chair gas spring/gas lift 1.TUV,BIFMA,calss 1~4 2.Adjustable 3.stroke D60~D260mm 4.weight: 0.7~1.2 KG/pc office chair gas spring/gas liftoffice chair gas spring,gas spring for office chair,adjustable gas spring,gas spring for furniture1.TUV,BIFMA,calss 1~42.Adjustable3.stroke D60~D260mm4.weight: 0.7~1.2 KG/pc office chair gas spring/gas lift