SEE COMPATIBLE PHONE LIST IN DESCRIPTION. NOT for Cell phones and ComputersDirect connect landline telephone headsets ONLY Compatible with Some Specific Phone Models from ShoreTel Plantronics Zultys Toshiba NEC Aspire Dterm Nortel Norstar Meridian Siemens ROLM Packet8. Compatible with Polycom: SoundPoint 300 301 335 430 450 500 (rev. E or later) 501 550 600 601 650 670 CX300 CX500 CX600 CX700 VVX300 VVX310 VVX400 VVX410 VVX500 VVX600 VVX1500 High Sound Quality for Clear Communication: Wideband Sound telephone headset enables natural listening experience, features Noise Canceling Microphone to reduce background noise, Acoustic Shock Protection Circuit to protect your hearing Most Comfortable Headset: Super lightweight office telephone RJ headset with adjustable headband to fit all head sizes, high quality and soft leatherette ear cushion enhance all-day wearing comfort Super Durable: Precision design, quality plastics, unibody headband construction, superior quality m