For more than a decade the CPR MICROSHIELD has been the leader in CPR barriers. Designed to protect the rescuer while aiding in the administration of proper CPR technique, it has become the standard by which others are judged. The positive one-way valve inside the airway enhancing bite block is designed for maximum protection of the first responder. It also assists in keeping an open airway while performing the head-tilt, chin-lift maneuver. The original CPR MICROSHIELD is conveniently packaged in an orange vinyl envelope style case and is still our most popular packaging option.