Part of the shipping of goods, in addition to Ningxia, Tibet, Xinjiang, Heilongjiang, Jilin, Inner Mongolia is not free shipping! Please contact customer service raw materials imported from Malaysia pure rubber refining, is dedicated aircraft parachute seat belt material. With a nylon rope woven into later, after the soft-treated. So take comfort, breathable, not hot, safety, health; durable, never collapse; and can be a good place into the blood circulation, eliminate fatigue; so you get to relax in the busy work, seemed more at work, pleasure. Its elastic properties: elongation 4 times 100% response rate, each chair to withstand the weight of the rubber strip 150KG, rubber life for more than 6-8 years do not appear degenerate broken loose. Elastic strips can easily be worn as a replacement, low maintenance costs, replacement and then is a new chair. Resistant to cold, heat resistance: -40 ℃> + 60 ℃, the surface is easy to clean. Express is based on weight, according to the square of the charge, a single piece of relatively large items shipping slightly more expensive. We are doing everything possible for everyone to find a cheap courier. Hope you forgive me! !