... service. 5 year warranty for the goods.TypeStroke for different kind of chairs.Boss chair: 60mm, 80mmOffice Chair: 100mm, 120mm, 140mm, 160mmBar Chair: 180mm, 200mm, 260mm, ... warranty(Much Better)Class 4---2.5mm, more expensive price, five year warranty (Best)Trade TermFOB Shanghai or C ... &F price if you need Company NameChangzhou Nantai Gas Spring Co., ...