Bi-directional Air Flow: As moist air flows through the breather's filtration system, it is cleaned of impurities and dried. Expelled air partially regenerates the silica gel and "back flushes" the particulate to prolong the life of the breather. Durable Construction: The desiccant air breathers are manufactured from rugged ABS plastic and impact-modified Plexiglas. Water Vapor Absorbent: Silica gel is chemically inert, non-toxic, non-deliquescent, non-corrosive and environmentally disposable.more Its internal structure of interconnected microscopic pores absorbs up to 40% of its weight. Color Indicator: As the gold silica gel absorbs water, it turns green to indicate that it has reached its functional capacity and that replacement of the breather is required. Dual Anti-static Filter System: The solid contaminant filters are designed to reduce the potential for explosion in dusty environments. Safety Sealed: To ensure a long shelf life and premium operating performance, each desiccant breather is individually sealed and vacuum packed to protect it from moisture before it is placed in service. less