*Discontinued* Replaced by the Plantronics HW510-POLY Polycom Headset This Plantronics HW251-POLY is Polycom IP phone compatible Headset (see compatible models below). HW251-POLY is the new standard in all-day comfort and reliability to telephone professionals. Enhanced receiver-side audio quality, intelligent flexible boom and stylish design provide greater headset flexibility. SupraPlus offers this monaural versions with a voice tube microphone. Certified for Polycom Soundpoint IP phone models: 300, 301, 335, 430, 450, 500, 501, 550, 560, 600, 601, 650, 670, CX300, CX500, CX600, CX700, VVX 101, VVX 201 VVX 300, VVX 310, VVX 400, VVX 410, VVX 500, VVX 600, VVX 1500, VVX 150, 250, 350, 450 Key Features: Includes a Polycom certified RJ-9 bottom cable - connects directly to the "headset" jack of your Polycom phone. No additional cable needed. Wideband improves speech clarity Enhanced audio for greater listening accuracy Durable, designed for the most demanding environments Comfortable, lightweight design Adjustable headband, foam ear cushions and comfort T-Pad design create a stable, comfortable fit. click-stop boom: Stays in position for clearer voice transmission. Low Profile: Features clear, adjustable voice tube. Quick call feature: Headband twists out of the way for convenient quick call pick up.