Flightguard PR3 design is scientifically engineered for performance. Pressure chamber tested, Mack's Flightguard earplugs are proven to regulate air pressure with a pressure regulated ceramic filter, pressure relief air channel, and soft flexible flanges. This design slows the rapid in-flight air pressure changes that cause discomfort and allows the ears to function more normally. Guard your ears against pain and fly in comfort with these pressure relief earplugs.