Walker's Nano Technology is a truly durable and invisible liquid repellent coating inside and out. One environmental adaptive listening mode, 50 dB. of hearing enhancement. Adjustable Frequency Tuning AFT. All Elite series in ear models have the following features: 4 digital sound processing channels, 20 bit audio processor for crisp clear sound, 8 band graphic equalizer, Nano-Tech water repellant coating, automatic feedback control, 20 percent smaller than Game Ear series 1, toggle volume control, sound activated compression, low battery tone indicator and a NRR of 20db. Operates on a number 13 battery. Includes Walker's field carrying pouch.