The Elvex SuperSonic Muff is one of only a few ear muffs that have achieved a 29 dB NRR rating at an independent and certified laboratory in accordance with ANSI S3.19-1974. The SuperSonic has the lowest headband force in its class. Pressure equalizing headband provides even fit and seal for a wide variety of facial configurations and sizes. The SuperSeal ear cushions provide outstanding seal and comfort. A flexible suspension allows muffs to automatically adjust to facial shape.