4Call K502QSCMB Dual RJ Telephone Headset Headphone + Noise Canceling Mic + All in One Smart Cord PL100 for Plantronics M10 M22 Vista Adapter and Cisco 7975 9971 Office Landline Desk IP Phones Direct connect headset, no additional amplifier or adapter required. Adjustable fit headband and comfortable ear cushions enhance for wearing comfort, even for long periods.WORKS ONLY FOR PHONES LISTED IN DESCRIPTION, BUY ONLY WHEN YOU HAVE ONE OF THE PHONES LISTED. CONTACT US FOR GUIDE IF YOU ARE NOT SURE ABOUT YOUR PHONE COMPATIBILITY Comes with Universal Compatible Smart Cord, Simple 8-position slide adjustment & Standard RJ connector, Connects to 90% desk phones using a standard modular plug. 8-position configurations: 1 Standard (most common) M-, R, R, M+ 2 Cisco IP phones 79xx series R, M-, M+, R 3 Ascom offce and Philips phones R, M+, M-, R 4 Japanese phones, NEC, Nitsuko M+, R, R, M- 5 PLT Vista Base R, R, M+, M- 6 Panasonic phones with modular plug M+, R, R, M- 7 Nortel digital phones and Avaya IP phones M-, R, R, M+ 8 Avaya Callmaster V and VI, Cisco R, M-, M+, R With two earpieces and a noise canceling microphone, this headset is ideal for noisy offices. It delivers high quality sound to both ears, enabling you to concentrate fully on the caller with minimal distraction & superior sound pick up. Quick disconnect feature enables you to disconnect quickly from the bottom half the cable, while still wearing the headset. With Mute / Volume Control built in.