CS540 Convertible DECT Wireless Headset provides enhanced professional performance so you can get more done even on the move. Noise-canceling mic reduces background noise interruptions, ensuring great audio quality. Roam confidently up to 400' from the headset base. Simplify collaboration by conferencing up to four headsets on a single base. SoundGuard, an acoustic-limiting technology, protects against acoustic shock (AS) by limiting sounds to below 118 A-weighted decibels for better listening comfort and protection against audio spikes. Adaptive power system optimizes for range and talk time by automatically downshifting to low power when the headset is close to the base, saving batter life. Charge lasts up to 7 hours of talk time. Enhanced Digital Signal Processing (DSP) provides more natural sound to deliver clear audio. Convertible design allows three wearing options: over the ear, over the head and behind the head.