The Prestan CPR Training Mask Adaptor set (50 pieces) is an economical and hygienic solution for training centers, replacing expensive mask valves with single-use valves for training purposes. Key Specifications and Features: Hygenic Design: The adaptors come individually wrapped to ensure sterility and easy distribution to trainees. Advanced Protection: Features a built-in air filter that prevents the passage of contaminants, providing a safe training environment. Wide Compatibility: Designed to fit all standard resuscitation masks with (15mm inner diameter or 22mm outer diameter) sizes. For Training Only: These adaptors are intended for training and educational purposes only and are not for rescue use.