3M ™ Peltor ™ Optime ™ III H540P3 hearing protection (passive). Helmet mount is available as an option. Developed for use in extremely noisy environments, especially in low-frequency environments. This protection features a dual-casing technology that minimizes resonance in the holder casing, providing maximum attenuation of high-frequency sounds. An acoustic connection between internal volume and volume between housings provides maximum attenuation of low frequency sounds. The sealing rings are wide and filled with soft plastic foam, which gives a very good fit and low contact pressure. Hygiene kit is available as an option