... Plug size :3.5mm Visang R03 VS-R03 Inner-Ear Headphone & hifi Headphone earphone The R03 is an upmarket professional-level earphone ... response and detail reproduction. Though tuned for increased bass, the R03 sound involving and natural at all frequencies, providing reference-level ... an audio professional or just a music junkie, the ViSang R03 will take your listening experience to the next level. ...