The ACS TM (Asherman Chest Seal) is a sterile occlusive dressing for treating open pneumothorax and prevention tension pneumothorax in chest injuries from gunshot stab wounds or other penetrating chest trauma. The unique one-way valve is designed to let air and blood escape while preventing re-entry of either. Proven more effective treatment than standard petroleum gauze, the ACS is standard issue for the US Army, the British Army and US Navy. The ACS is 5.5” in diameter, includes a gauze pad (4” X 4”) to clean and dry the wound and is clear so the wound can be observed