I recently got a military backpack and wanted to attach a medical pouch to it. I found that there are attachments online but I did not want to wait for one. After a minute or so in CAD and 15 min of printing I got what I needed. I hope you will find the print as useful as I did. 

UPDATE: I have added a new version that has an extrusion and two M3 Bolt holes, so now you can screw in things to the attachment and then attach it to the backpack! There will be more to come! The opportunities that this new version provides are limitless!

 Happy printing!