Poly EncorePro 540 with Quick Disconnect Convertible Headset TAA - Mono - Mini-phone (3.5mm) - Wired - 20 Hz - 16 kHz - On-ear - Monaural - Ear-cup - 2.92 ft Cable - Omni-directional, Noise Cancelling Microphone - Black | Hp | | Poly EncorePro 540 with Quick Disconnect Convertible Headset TAA | Mono | Mini-phone (3.5mm | Wired | 20 Hz | 16 kHz | Black | Best Buy