The Bose mono channel on the plug is smaller than most and other headsets wear out the receptacle and the Bose headsets then don't make good contact and create static. By buying the stereo-mono adapter you make better contact with the adapter and the adapter has a wider channel! When you look at them you don't notice a big difference but it makes a differerence. If your company has DC on the airplane, compare the plugs against your Bose you will see a difference on the audio plug (one with 2 bands on the Bose, the thicker one) and then look at the wider band, that's your mono! Sorry typing from the phone....