Got an iPhone 7 recently, but I don't want to use the dongle to convert my 3.5mm headphone to lightning. I don't want to switch to bluetooth headphones for now because I'm quite comfortable with my headphone right now. My top priority will be battery life, price comes second. I heard that Etekcity's Roverbeats Unify does a pretty good job on battery life (200mah battery for 10 hours), but customers reported that it doesn't support phone calls. It only costs 20 bucks which I think is worth to compromise. Then there is another receiver XB10 from Astell & Kern, which cost $189 but comes with some audiophile functions (which I'm not familiar with cuz I only listen to AAC/MP3), and able to answer phone calls. However it only lasts about 5 hours (and even with a 350 mah battery). Is there any other good portable BT receiver(s) to recommend?