Sony MDR-W08L Vertical In-the-Ear Headphones (6 pack) Case pack of 6 pieces Vertical in-the-ear design reduces size and weight to the bare minimum; comfortable hour after hour Neodymium magnet for maximum energy in minimum size; Neodymium is comparably more powerful than conventional Samarium Cobalt or Aluminum magnets Frequency Response : 20Hz -20,000Hz Sensitivity : 104dB/mW