I need to buy a headphone that does not harm my ears, because i like to listen audiobooks everydays. Many thanks!
I haven’t heard of a headphone that’s specifically designed not to harm a user ears. Basically all headphones can be used safely provided you do not turn the volume to the loudest, likewise all headphones (even the most expensive ones) can harm your hearing if you abuse them and turn the volume to the loudest for a prolonged period of time every day.
Nothing will harm you unless you overuse it - just don't listen to music at full volume. If you are looking for a headphone for best quality then I would recommend - Skullcandy.
I bought my set of Philips SHE3590BK/10 headphones at the flea market for $5. They served me for 3 years already and I never had pain in the ears or headache, whatever. Sound is clear, isolation from noise is good. Why people pay cost of a suit (or a used car in some cases) for a pair of headphones - just amazes me.