NEW T400 Headset Headphones Ear Phone for Plantronics A100, S10, S11, S12, S50, T10, T20, T50, T100, T110 Ip Telephone, Black Calltel T400 polaris Monaural Over-the-Head quality headset Soft leatherette ear cushions for all day comfort 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 Polaris models are for phone systems with built-in amplifiers . Connectivity technology: wired