The CTS-C205S Neck Loops coil transmits the audio output signal of a radio into a magnetic field covering either side of the user head. This field can be detected by a wireless  earpiece . Therefore the use of wired earphones or headsets is no longer necessary. Neck Loops is very comfortable to wear and can be easily concealed under clothing. Its magnetic field allows the user total freedom of movement. 
Virtually, change jack socket on Neck Loop, any kind of wired earphone even such as an MP-3 player, data recorder, used toCTS-206,Completely-in-the-Canal wireless earphone or CTS-207.
All  Neckloop has two special adapter, one use for Motorola/ NOKIA-LP4 mobile phone, so it can use for Motorola mobile phone such as A1200/W220/C119/E680/C118/W205/A810/W161/W230/C261/W360/C139/C168i/A728/V360/W338/W270/W181/W213/W206 etc (produced after year of 2006), also can use for NOKIA-LP4. Such as NOKIA 6080/6101/6111/6125/6131/6136/6233/6234/6270/6280/6288/N70/N71/N73/N80/N93/N93i etc.(produced after year of 2006).
Another special adapter for MOT/ NOKIA-LP3 mobile phone. such as NOKIA 1650/2630/3500C/5200/5300/6120C/6300/6301/6500S/7500/8600L/E51/E90 etc.