One-piece design with no seperate inner bite block. Clear colour coding for easy identification. Synthetic rubber tip reducing the risk of trauma. Comes with self seal bag. Single use. When the disease by breathing casualty keep the airway patency, breathing membrane into the middle of the mouth of the wounded mouth, from another blow for the wounded, the check valve will prevent the plastic nozzle with a breath into the mouth of the wounded and rescue personnel. It is the best tool for artificial respiration. Hypertension and epilepsy so easy syncope patients should also be equipped to carry this treasure to the rescue!