this bag material is usually composed of four layers that are BOPP/AL/PA/PE, and can be made into ESD vacuum type to well protect inside products from static, electromagnetic interference, moisture and direct sunlight. the important is that we can design the material structure as customers' required. the bag is normally applied to large machines, electronic components, vacuum packing, telecommunication...the product has superior puncture resistance and anti-static inner and outer layers with a surface resistance of 108 - 1011ohm. All sizes are available in open flat, zip-lock, and kinds of tri-dimensional Styles.