Advanced technology, potentiometer-controlled signal processing designed to provide an accurate sound. Feature Summary: Linear Processing with Output Compression Limiting provides linear amplification without the distortion that accompanies peak clipping. Dual Time Constant Output Compression design prevents audible artifacts sometimes associated with compression limiting. Advanced Directional Microphone technology utilized to enhance speech understanding in noisy environments. Precise Potentiometer adjustments ensure an accurate and consistent fit. Available in custom ITE, LP, HS, ITC, MC and CIC styles. Volume control for all styles. Screw set volume control standard for CIC. Indicator Tone for low battery.