TDK BA100 is only single BA phone I have experience with. Discontinued, but was available for awhile at TJ Maxx, Marshalls, Ross stores for like $10. Can find them on ebay every once in awhile. Also set my alarm for 2am so I could buy a pair of those T6 headphones. Got a pair of them and the Bluetooth ANC earphones for 38 shipped. Pretty unbelievable. It will be interesting to compare the T6 at $30 to Sony 1000XM2 at $300. The Sonys have the best ANC going right now imo.