CPR masks are specialized devices used during cardiopulmonary resuscitation to provide a barrier between the rescuer and the patient. They help deliver rescue breaths while minimizing the risk of disease transmission. These masks are typically made of flexible plastic and come in various sizes to fit both adults and children. Most CPR masks feature a one-way valve that allows air to flow from the rescuer to the patient but prevents exhaled air from returning. Some masks also include a built-in oxygen port for enhanced ventilation. They are essential tools for first responders and bystanders trained in CPR.