Koss SB40 Full Size Communication Headsets - Stereo - Mini-phone - Wired - 120 Ohm - 20 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - Noise Canceling Stereo - Mini-phone - Wired - 120 Ohm - 20 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - Noise Canceling

Koss SB45 Communication Headsets - Stereo - Mini-phone - Wired - 100 Ohm - 18 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - 8 ft Cable Stereo - Mini-phone - Wired - 100 Ohm - 18 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - 8 ft Cable

Koss SB45 USB Communication Headsets - Stereo - USB - Wired - 100 Ohm - 18 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - 8 ft Cable - Noise Reduction Microphone Stereo - USB - Wired - 100 Ohm - 18 Hz - 20 kHz - Over-the-head - Binaural - Circumaural - 8 ft Cable - Noise Reduction Microphone

Koss CS100 Communication Headsets - Stereo - Mini-phone - Wired - 32 Ohm - 30 Hz - 16 kHz - Over-the-head - Binaural - Supra-aural - 8 ft Cable - Noise Canceling Stereo - Mini-phone - Wired - 32 Ohm - 30 Hz - 16 kHz - Over-the-head - Binaural - Supra-aural - 8 ft Cable - Noise Canceling