Universal Fit and Size: This disposable single way valve is designed with a 22mm specification, ensuring it fits most standard CPR mask and devices. The compact size of 4*3cm makes it easy to store and carry in emergency kits Function: Specifically crafted to prevent direct contact with the patient's mouth, nose, and face during mouth to mouth resuscitation Sturdy Material: Made from quality PS plastic, this CPR breathing valve is resistant to and alkali corrosion, as well as high temperatures, ensuring reliable performance in various emergency situations Effective Single Way Design: The single way valve mechanism allows air to flow into the patient while preventing any backflow of air or bodily fluids towards the rescuer Convenient Packaging: Each package includes 10 breathing valves, providing ample supply for training sessions or multiple emergency scenarios. Ideal for first responders, medical professionals, or personal use in first aid kits Size Chart: 4cmx3cm/1.57inchx1.18inch Package Includes: 10CPR Mask Replacement Valve Note: Please allow slightly errors 1-2cm/0.39-0.79inch differences due to manual measurement.