Integrative injection molding with good strength, friction and airproof, dampproof and dust resistant performance. Self-choose inner lining or control panel for instruments to realize easy carring. Self-choose inside lining, including static electricity elimination foam or EVA inner lining, cut them into network-like foam in advance in order to make all kinds of core space. There are areas for sticking logos both on the lid or bottom of the case. In the front of the box, there is a knob with obturating ring which is called pressure balance valve, to adjust the inside pressure by hand. With handles, padlock design. Color: Black, yellow, orange, military green.