Providing the highest-rated protection available for low-frequency environments, the MSA HPE Cap Mounted Earmuffs are designed specifically for very high noise levels and are ideal for airfields, power plants and other areas with intense noise. Super-soft ear cushions guarantee all-day comfort while ensuring full-time protection. The NRR or dBA may vary depending on the hard hat your hearing protection is being attached to. Please reference the hearing protection user manual for specific performance ratings.