they only charge $9. By the end of the day (and often well before), theyd end up being very uncomfortable and outright painful. The audio is crystal clear, and the 7. It?s rustic and easy to install my husband said:) Just needed something for a few tops that I don?t put into my dryer and or dresses. You can always use a higher wattage adaptor but you should not use a smaller wattage one. They don?t drain the battery too bad. If you dont want to spend money every couple of years on wired ear buds, then go with a bluetooth model, or be more careful than I am. However I have some durability concerns about the IE 40 Pro. I use a headset with my VOIP telco line and the quality on this is just as good. If you want good headphones youll have to spend a little more than 20 dollars.