Free gas spring (Zhi Chenggan) (gas spring Lift) is the most widely used gas spring. It mainly plays a supporting role, only the shortest, the longest two positions in the trip can not be stopped by itself. In the automotive, textile machinery, printing equipment, office equipment, construction machinery and other industries, the most widely used. Free gas spring with its light, stable work, convenient operation, price concessions, etc., in the automotive, construction machinery, printing machinery, textile equipment and other industries until the application of gf. Or alpine environment, acid or alkaline environment, etc..