Fits 9mm Glock magazine wells, so it will work for all Glocks (except the small single stack ones), all AR-9 / AR-15 in 9mm. If printed with an infill of >90%, it is as sturdy as it can be.
Feel free to print for yourself, friends etc. - but remember, the license does not allow selling them anywhere.
Update 03/18: Added the file with the rounded top, otherwise identical
PLA will be fine, I did not test any other materials