It looks like hand blowing, there is a fine feeling slightly different in shape one by one. I can understand the difference in color of sample with high transparency. Strength is also very useful. Unlike the screw because the lid is a drop-in type, it is very convenient when opening and closing frequently. The lid is tapered and it is fixed naturally. If you are stuck on arrival, do not pull by force, tap lightly with kitchen knife or hammer's handle etc to give off vibration naturally.
One out of the two, roughness of the fitting of the plug and the body is poor accuracy, watertight can not be obtained. It can not be used for preservation of solvent etc. Quality level is low, quality control is not done. (Although it has passed considerably since purchase, I would like to exchange)