4-pin RJ9(4P4C) Plug, NOT RJ11 plug Headset Headphone Call Center Desk Telephone Monaural Mic Mircrophone* Provides all day comfort, clarity and durability for Desk Telephone.* Offers the added value of a noise cancelling microphone which will eliminate up to 90% of the background noise making it ideal for use at home or in the office* Excellent sound quality, lightweight, durable and comfortable* Adjustable headband* Suitable for all telephone* Color: Black