One of my first prints for my daughter followed shortly afterwards a request one for her friend, a little on the narrow side for my Pixel phone and it's dbrand case but fit my daughters iPhone 11 and random Amazon case perfectly
If its not to much...though I probably could have scaled it a little larger but then its footprint would grow. I measured my dbrand case at a little over 13mm and then my work iPhone 12 with a Defender case at 14.4mm. I would say that 15mm is probably a good number for others probably looking for the same....being that the opening on the two I printed is a tad over 11mm. Either way...print worked awesome!