I am glad to know you have received the sample. Please be kindly informed that we could not put the valve because if yes, the cylinder will be considered to be fully sealed equipment and the FedEx refuses to ship the same in case any danger happens. Ms. Chompoo, could you please fit the valve by yourself please? And the place where you fill the cylinder could help fit the valve.
If you still have trouble to fit the valve, please do feel free to let me know.