Sennheiser SH 230 IP Headset - Mono - Wired - 180 Ohm - 150 Hz - 6.80 kHz - Over-the-head - Monaural - Semi-open - 3.28 ft Cable - 504012 Sennheiser 504012 SH 230 IP Headset - Mono - Wired - 180 Ohm - 150 Hz - 6.80 kHz - Over-the-head - Monaural - Semi-open - 3.28 ft Cable