A VBL is a non-breathable materials that does not permit the transmission of moisture by means of it. They are generally product of fabrics like silicone-impregnated nylon, polyurethane-coated nylon, or Mylar; and https://joyceeghl326836.blogspothub.com/29578439/not-known-facts-about-vaporba-celare-510-thread-battery