... year warranty for the goods.Type Stroke for different kind of chairs. Boss chair: 60mm, 80mm Office Chair: 100mm, 120mm, 140mm ... , 160mm Bar Chair: 180mm, 200mm, 260mm, 330mmSample Free.Color Button color: White, Black, Orange, Green etc.Class Class ... is different from the thickness of medium tube & outer tube. Class 1---1.2mm, cheaper price ...