In ear headphones noise cancelling headphones series trevi hmp type of fitting in ear transmission mode wired features microphone call function answer call sound function active noise reduction impedance 32 ohm frequency response 20 20000 hz max power handling 100 mw magnet type neodymium length of cable 12 m types of cable flat cable tangle free jacks 35 mm 4 pole jack plug for apple blackberry jack shape straight colour green material