The Bull's Eye Ultimate "10" has the highest noise reduction rating on the market for any earmuff that has been tested by an accredited test facility. Dual cup design minimizes resonance in the system and gives a smoother attenuation over the whole frequency range, improving the speech intelligibility. The cups have different resonances, and they're separated by a compressed layer of special foam material. This absorbs energy in the same way as a shock absorber, thus reducing the sound transmitted from the shell of the cup. Noise Reduction Rating: 29db Aearo Peltor