The headphones that only get worse and worse with each firmware update.
In the beginning I was very happy, that it switched between 2 units worked well and no strange errors. Over time, I began to notice that the left ear now had only about 50% volume out of the right, a known error, and switching between devices got worse and worse. After a number of firmware upgrades, 1s sound started to disappear every minute, when it "checks" with the other device, sick annoying when sitting in conference calls. Called the support and tried to get help, the only thing they could do was to send the headphones to Belgium, it would take at least 2 weeks to get back a pair of replacement headphones. Asked if they could not reserve money on a credit card as a hostage in exchange for sending a couple of new tricks first, and then that you return the old ones, as you are quite dependent on them. No! Nothing Bose deals with, get rid of them for at least 2 weeks only alternatively.
With by far the worst iOS app to control the headphones, combined with brutally bad firmware that only gets worse and worse with each version they release, with the ultimate combination of really garbage-bad support, this is the last time I will ever buy anything from BOSE again.