Dialpad Headset, Coodio Corded Phone Headset [Call Center] Telephone Headset [Noise Cancelling] [Protein Earmuff] Monaural Headphone with Mic Microphone 4-Pin RJ9 for Desk Telephone Dialpad - HS1 Hands-free, protein earmuff provide all day comfort. Boom-style noise cancelling microphone adjustable for optimum level Reversible for use with either ear, comfortable, lightweight design Monaural headsets are widely used in quiet working surroundings. Excellent for use with Call Center Service, Telephone Counseling Services, Insurance, Hospitals, Banks, Telecom Operators, Enterprises