4 Two pre-installed rechargeable AAA batteries (accessible in the right side headphone by pushing down the small catch at top above the ear cushion, and pulling off should you ever need to replace them. UPDATE: This headset only lasted 2-1/2 months. bz0482 These are terrible and I wish I spent the money from the dealership. After hours of wearing them, I forget I have them on. bz0482 If you want to use this in another house, you should carefully pack it in the original packaging before transporting. bz0482 I bought these for my son, who admittedly loved them, but the design of making the in ear parts detachable from the cable has led to their demise. There seems to be little to no quality loss in the Bluetooth signalThey block out 80% of outside or background noise. Looking at my other worn shoes and sandals, this uneven wear can be seen in a much less pronounced way, but has never of itself prevented good wear from being obtained all over the soles. bz0482 on low gain i still had to keep the volume knob at about 9 oclock. The headphones worked fine just not the mic.
bz0482