I really liked the idea of these DIN tape cassettes for organizing my cut tape parts, but found the latch mechanism on the original to be a little fiddly. This version changes the latching spring and catch orientation to make it easy to clip and unclip to the rail with one hand. 

In addition, I added a couple windows for 1) advancing the tape after it has been pushed back inside, and 2) seeing if the tape is about to run out. Finally, I added a small inset on top to make it a little harder to accidentally snag the edge of a label. 

Note: the additional clearance required for the new latch means the original legs won't work! I've updated them to fit. You can now attach them to the DIN rails either with a captive m5 nut/screw, or (my favored method) with a zip tie.

For a great bottom-mount DIN rail version, try this one: https://www.printables.com/model/421230-smd-magazine-for-din-rail