The Jabra PRO 920 is a professional-grade wireless headset designed for maximum performance at an entry-level price. Crystal Clear Sound - Digital Signal Processing (DSP) in Jabra audio devices will remove background noise and echo as well as protect the user against sudden high peaks in volume. Wireless Freedom up to 300ft. Noise Canceling Microphone reduces unwanted background noise and are ideal in crowded and noisy, open office environments. Peak Stop - Peak Stop technology immediately removes potentially harmful loud sounds or tones before they reach your ears and keeps the sound level within the safe range to protect your hearing. Supports the DECT 1.9 standard wireless technology. Talk Range feet: Up to 325-Feet Talk range defines how far away you can be from the headset base. Conference call capacity: 4 Up to 4 headsets can be joined to one base at the same time for conferencing call purposes.