Plantronics HW251N SupraPlus Wideband Headset (64338-31) Noise-Canceling microphone filters out background sound HW251N P/N 75100-06 Uses Plantronics QD Quick Disconnect Connector. Must be used with Plantronics Amp or with proper phone or USB adapter cable Connectivity Technology: Wired, Earpiece Design: Over-the-head, Earpiece Type: Monaural, Host Interface: Proprietary, Microphone Design: Boom, Microphone Technology: Noise Canceling, Product Model: HW251N, Product Series: SupraPlus, Standard Warranty: 2 Year Easy Lightweight Wear -Leaving One Ear Uncovered For Person-to-Person Conversations