I made the holder for iPhone 6 first, and enlarged for fit the iPhone 6 plus also. I didn't print it out but if you make this please feedback here then I can (or you can) make it even better, enjoy!
Inside is a little bit bigger than iPhone6 plus, it's 163mm.
===UPDATE 2018/03/21===
Here is the smaller holder for iPhone 6 / 7: https://www.thingiverse.com/thing:694199
| iPhone-6-plus-card-holder.STL | 951.0KB |
