Review on Sony - C400 Wireless Behind-Neck In Ear Headphone White (WIC400/W) by Kritbodee Chaicharoe ᠌

You should use headphones. The quality of the sound is standard; it might be improved with the use of an equalizer, but is otherwise unremarkable. Long-lasting and quickly-charged batteries. The effects on the neck are indiscernible and the garment is easy to wear. The wires are just superficially thin and weak. They have length regulators too, but they merely exist and are ineffective; the wires gently slip through the rubber band that is supposed to keep them in place. However, I've heard that all wireless headphones get periodic signal drops, which is the worst part. While on the subway, the sound will play without any gaps; but, if you're out and about and happen to be near any transmitters that use the same frequency as your headphones, the music will suddenly stop. It's really frustrating, and it might make you want to throw away your headphones altogether.