Easy to Operate: Quickly release danger with only one button trigger in emergency while supporting self-rescue Preloading: Make the rescue quicker and easier, saving valuable time in emergency situations Consistent suction about 33KPa: Provide instant pressure to relieve choking, and ensure optimal results every time Safety: Greatly reduce the damage caused by mask pressure to face and neck, eliminating the risk of secondary damage caused by the blockage going deeper 3 Different Size Masks: Cover almost all people except infants. Make sure the mask fits the face and forms a vacuum environment