I use this one:
I also get MQA from Tidal with a Green LED from my iPhone this way. A very capable portable set!
Thank you. I did a bit of research on the side:
The other one (Lightning to USB 3 Camera Adapter) with the additional lightning port lets you supply more power through it so that devices which require more power are able to function, otherwise iOS wouldn't let the device draw more power than the battery can allow.
Another benefit with this dual port adapter is that you could charge your phone while you listen to music simultaneously. One caveat, though, is that USB3 transfer speeds work only on the bigger iPad. iPhones and the rest are capped at USB2. But this does not really concern us audiophiles because the speed of USB2 is more than enough as far as I'm aware.
What I find mind boggling, though, is the fact that you need one of these little adapters by Apple themselves despite having an actual lightning cable that you could plug straight in. It seems like Apple has put a chip inside it with an actual firmware that communicates with the OS and controls power output. On one of the videos, when the guy plugged the adapter in, a pop up appeared on screen saying that the adapter's firmware is being updated.
This seems to be the only way to get audio out of an external DAC on iOS.