Sennheiser SC 135 USB-A and 3.5mm Mono Headset 508316
Amazon.com: Factory Essentials HD251QD with U10 - Mono headset with USB-A Adapter. Comparable to Plantronics SupraPlus HW251 with DA45. Works with Phones and PC : Electronics
Jabra EVOLVE 40 MS Mono Headset 6393-823-109 B&H Photo Video