Used to replace old wire on my overearheadphones. Advertised at 2,100A I bought the size 12-18 month in May, her first birthday was May 1st. You have to unpair from the first device and then pair with the second. I purchased this back in May of 2013 for about $200 from Amazon. They also stay very well too. I shared on Instagram &people loved them too! The volume is weak. The music is equally fantastic, and although it doesnt quite live up to Zero or 5 in my opinion, its still fun to listen and play to and adds serious depth to the game. I used it on an older BMW car.