US Cable New Headset Headphone For Avaya 9620C 9620L 9621 9630G 9641 9641G 9650G 9650C About 8-feet cord with RJ-9 modular plug lets you walk away from the phone while still wearing your headset Polaris models are for phone systems with built-in amplifiers Direct connect over the head headset, no additional amplifiers or adapters required, most easy setup headset solution. Most easy setup headset solution. NO Mic Mute / Volume Control built in. Super Lightweight, Super Durable Headset with Comfortable ear and mic cushions Compatiblity(Only compatible with telephones with a built-in amplifier. Some other specific Avaya 9608 9610 9611 9611G SNOM 320 360 370 720 760 Polaris models are for phone systems with built-in amplifiers No Quick-Disconnect features included. NO Mute / Volume Control built in.