Polycom Compatible Plantronics VoIP Noise Canceling EncorePro 530 HW530 Headset Bundle for Polycom IP 300, 301, 335, 430, 450, 500, 501, 550, 560, 600, 601, 650, 670 | CX 300, 600 700 | VVX 300, 310, 400, 410, 500, 600, 150 Phones Bundle of 2 items - Plantronics HW540 Headset and Polycom telephone interface cable Compatible Polycom Phones Includes all 3 wearing styles - over the head, on the ear, and behind the head Ultra Noise-Canceling microphone filters out background sound