The Etymotic Music Pro Elite Rechargeable Active Hearing protection is the latest in advanced hearing protection technology. Designed for Musicians who want to hear naturally but need protection when hearing is at risk. Using active technology that constantly evaluates incoming sound the Music Pro Elite gives you two modes of operation. The Low mode gives you transparent pass-through audio under 90db. When the 90db threshold is passed it gives you 15db of attenuation for material above that level with a super-fast attack and release with the effect of only attenuating that sound. If it's a quick snare hit, you will hear the natural sound of everything else except that the snare, which will be attenuated as briefly as it happens and then levels go back to normal. If it's a steady guitar amplifier sound over 90db the sound will be attenuated as long as it is present. In High mode you get 6db of natural level gain under 90db with 9db of attenuation over 90db. The battery life is unprecedented in that out of a single charge on the ear buds you get 16-20 hours of use and an extra15+ charges out of the case itself. The Etymotic Music Pro Elite is a real revolution in hearing protection for musicians.