Features HIFI Classic 50MM Headphone Speaker Part Single piece production mylar paper molding 32ohm Aluminium-Copper voice coil materials NefeB Magnets,powerful bass,very good in the middle and high frequency voice resolution,female voice young and clear.background misic in full view. Packaging 2 Headphone Speaker unit Instructions Please test the speakers with a multimeter before soldering. The colored spot is for positive pole +, the other side is for negative -. Soldering with less than 3 seconds. Otherwise, the voice coil or circuit board can be burned out easily.