The zip file contains all the lowercase letters written with the ACME font individually saved each as a .stl file plus a .stl file containing the entire alphabet.
The Alphabet.stl file, containing the entire alphabet, was printed with an Ender3, it can happen that, for the Delta printers, the image is too big, in this case you can scale dimensions with your printer software.
Created with Fusion 360
Extrude 4 mm
Have fun and good 3D printing!!