Thing allows you to mount 3.5-inch device (like FDD - Floppy Disc Drive or Card Reader) in to standard 5.25-inch PC Drive Bay (meant for mounting DVD alike devices)
I have printed in ABS without "Tension Release Features" but added 12mm brim.
The thing is made of two pieces; “Chassis” and “Front Bezel”. There are pins designed in order to hold them together. However I would recommend you to glue them together.
There are two types of .stl files; two files prepared for ABS (they include 0.6% Shrinkage Factor and Tension Release Features) and another two for PLA printing. The .stl file names include "ABS" or "PLA" notice.
In case of ABS printing, you can easy remove Tension Release Features by deleting rows under "//printing tension release in 5.25 wall" and "//printing tension release in 3.5 wall" in .scad file.