WNC-2100 Wireless Noise-Canceling Bluetooth® Mono Headset - Andrea Communications
Logitech H570e Mono Headset Black 981-000570 - Best Buy
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HK375-S In-ear wireless mono headset - Motorola
Amazon.com: Verbatim Mono 3.5mm Headset with Microphone and in-Line Remote : Electronics
Mono Headphones
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Voyager 5200 Office & UC Series - Mono Bluetooth Headset | Poly, formerly Plantronics & Polycom