Beeswift Max Corded EarplugMAX (NRR 33) pre shaped foam earplugs feature a smooth outer skin for maximum user comfort. With an NRR 33 rating, the MAX is the highest rated disposable earplug in the U. S. The smooth, soil resistant skin prevents dirt from penetrating the surface prior to insertionattenuation tested in accordance with ANSI S3. 19 1974. Key Features: Pre shaped foam for maximum comfort. Smooth, soil resistant outer skin to prevent dirt penetration. Highest rated