Sennheiser RS 195 RF Wireless Headphone System Closed back, circumaural headphone system with excellent digital wireless audio transmission delivering range up to 328ft/100m (line of sight)Connectivity Technology: Wireless Selectable hearing boost presets with an additional noise suppression mode for clearer dialogues and superior speech intelligibility Music listening mode for increased dynamic range Multi-purpose transmitter supports both Digital and Analog Inputs in addition Automatic and Manual Level Control - also functions as 'easy-charge' cradle and docking station for the headphones Not compatible with Bluetooth technology Compatible with analog and digital audio inputs, as well as toggling between inputs THD, total harmonic distortion: &lt;05 % at 1 kHz, 100 dB SPL Two year warranty when purchased from an authorized Sennheiser dealer NOTE: Check User Manual in Technical Specification before use