a. The materials for making any size cylinders arrived in our factory, after checking the basic size, the element inspect and tensile testing should be done, only meeting the standard, then put into production.  

b. It is essential to making hydraulic testing and weld examination during the production.  

c. We must make sure that all products sold are safe, so the explosive test, X-ray test and stretching test will be done by using a random sample in each bath of finished goods.