Polycom Compatible Plantronics VoIP Noise Canceling EncorePRO HW720 Headset Bundle for SoundPoint&reg; VoIP Phones: IP 300, 335, 450, 501, 550, 560, 600, 650, 670 | VVX300, VVX310, VVX400, VVX410, VVX500, VVX600, VVX1500 | CX300, CX600, CX700 BUNDLE OF 2 ITEMS - Plantronics HW720 EncorePro Headset and Polycom compatible telephone interface cable. COMPATIBLE POLYCOM PHONES: IP 300, 301, 335, 430, 450, 500, 501, 550, 560, 600, 601, 650, 670, CX 300, CX 600 CX 700, VVX 300, VVX 310, VVX 400, VVX 410, VVX 500, VVX 600, VVX 1500. IMPROVED CONNECTORS: Quick Disconnect - Allows for easy disconnect from phone without removing headset. Less strain and fatigue to hands and fingers with improved ergonomically contoured connector easy on/off of quick disconnect. PLANTRONICS HIGH QUALITY DESIGN: High quality lightweight nylon composite materials provide an ultra-lightweight design - taking comfort to a new level. GLOBAL TECK GUARANTEE: 100% Happiness with your purchase. Contact us if you have questions about compatibility with your phones as this adapter is only compatible with the mentioned Polycom phones.