Sennheiser EP 01 - - Earpiece headphones stereo / mono
Sennheiser 231 Mono Bluetooth Headset- The ultra-secure bluetooth wireless headset is the perfect choice for financial, medical, government and contact centers or anywhere sensitive conversations happen
Sennheiser PC 2 CHAT Mono Analog Headset for PC, Black (504194)
EPOS Sennheiser IMPACT DW Pro 1 ML Mono DECT Wireless PC, Phone Headset DW 20 ML | eBay
Sennheiser Consumer Audio PC 7 USB - Mono USB Headset for PC and MAC, Black (504196)
Sennheiser SC 135 USB (508316) - Single-Sided (Monaural) Headset for Business Professionals | with HD Stereo Sound, Noise-Canceling Microphone, & USB Connector (Black)