You won't find a low-impedance model, nor a U174 plug. You can get an adapter, or convert the plugs, either way works. Low-impedance headsets are rare in the US, only the military uses them very much. If you need an in-the-ear low-impedance headset, contact Quiet Technologies. The owner was very helpful in getting mine set up properly. He may be able to provide a low-impedance model.