Slides nicely in and out of a pocket, holds tight and gives you better leverage on the keys. I am personally really happy with this little design i made, i am using it two years now, still the first print. 

!! PUT THE AIRTAG INTO THE PART PRIOR TO ASSEMBLING !! - it is much easier to do so

2x M3 screws

2x M3 nuts ( + some locktite or nuts with the blue band around them will stay tight for longer)

some spacers, i recommend tpu if you will print some

I used pla and its fine for two years now.

40% infill, 4 perimeters, no supports