Lebowski is dead on. Especially in the Bose comparison. I have flown with the Bose as well. And I lost battery power with them during a flight, not fun. I worked for a aviation catalog and dealt with both the Bose and Telex guys. Both were great but when the Telex people let me try that 50-D I was sold. I ended up buying the ANR 4105 which I really like as well. When I was flying freight for Flight Express, they worked great in the cockpit, even when the batteries died. I would get a little over 40 hours from a 9 volt battery. My point from all of these ramblings is that the Telex products keep things nice and quiet even if you do lose battery power.