ETY-Plugs earplugs use patented technology that replicates the natural response of the ear canal so that sound heard with these earplugs is as clear as the original, just quieter. ETY-Plugs earplugs have nearly the same fidelity as Etymotic's Musicians Earplugs (custom earplugs worn by professional musicians) Hearing loss is a function of exposure time, the average sound level, and the peak level of very loud sounds. Exposure to excessive noise can cause permanent hearing loss depending on the intensity and duration of the sound. Some persons are more susceptible to hearing loss from high-level sound than others. Protect your ears. In high-noise environments, wear Ety-Plugs. Includes one pair of Ety-Plugs, carrying case, black neck cord and instructions.