AGPtek&reg; 4-pin RJ9 Crystal Head Super Telephone Monaural Corded Headset for Call Center, Phone Sales, Counseling Services... For phone sales, telephone counseling services, insurance, hospitals, banks, telecom operators, enterprises etc... 330 degree adjustable boom to ensure the best call quality Microphone noise abatement, can reach the aviation noise reduction level Screw headphone cable, avoid damage during use the use of flexible metal hose, MIC positioning accuracy, structural design, durable, comfortable to wear