In this video I demonstrate what accessory(s) are required to connect the AudioQuest DragonFly Black or Red to an Apple iPhone that has a Lightning port. The phone used in this video is the iPhone 6s.
The Original Apple Lightning to USB Camera Adapter is what AudioQuest states as necessary. Android devices should work with any micro-USB to USB Female adapter. There are 2 models of the Apple Lightning to USB Camera Adapter, BT-MD821ZM/A and the newer BT-MD821AM/A. Both will work. If you have iOS 9.2 and above, both of them can also be used to connect memory flash drives, keyboards and other USB accessories to your iPhone. Earlier versions of iOS would still work with the DragonFly but not with other USB devices.
Note, it is also possible to use the same accessory to connect an iPhone to the older DragonFly models, original and the newer DragonFly 1.2 although their power requirements mean that they would need to be connected through a powered USB hub.
There are several iOS Apps that will allow the user to listen to FLAC files at their native resolution. The DragonFly range only supports up to 24 bit @ 96 Khz (which will sound better than 24 / 192 in small devices like these). If a higher resolution FLAC is played, the DragonFly will play them at 24/96. The App that I am using is called FLAC Player. It is the only one I have used with the DragonFly so I can't comment on others.
Please feel free to ask me any questions below.