Bowers & Wilkins PI7

PI7 is a high performance in-ear headphone designed to deliver the highest 
quality mobile personal audio experience combined with the convenience of 
wireless operation and the serenity of no PI7 incorporates a rechargeable battery case. When fully charged, depending 
on the degree of Bluetooth, Adaptive Noise Cancellation and Ambient Pass- 
Through use, the battery case can provide up to 20 hours of continuous wireless 
media streaming with noise cancellation enabled at average playback volume 
levels.ise-cancellation.