The L 300 Ergo Pro includes both a convertible headset and amplifier in one and features inline volume control and mute switch for the ultimate in convenience. Compact and convertible, the amplifier footprint is 20% the size of standard amplifiers clearing up valuable desktop space. The L 300 Ergo Pro is compatible with virtually all phone systems, including Nortel, AT&T, Siemens, and Avaya.