These are designed to feed cloth straps in one way and out the other so that they can be tied (the straps) around something such as a pole.
You super glue them to the cloth or canvas you want them on (flat side down), once dry, take a sharp hobby knife (or something similar) and carefully cut out the holes in the fabric. It is then ready for use!
I used this on the top of a garden tent top that was blowing off using the velcro that came with it. Now, it stays put!
The X3G files are for the Makerbot Replicator 2. One allows you to print 7 at a time! Printing one took 10 minutes. Though printing 7 only took 50 minutes! :)