Its a spool for a bungee cord or bungee cords for your helmet it goes on top with a Velcro strip and restrains your NVGS from falling due to mount malfunction and other issue of the sorts but yeah glue the cord to the wall of the separate part attach them and through the little hole put a screw with a large head s it doesn't fly off but spins specifically a thin screw and a large head for the screw and i will spin freely however it should have some friction but more of less friction so it rubs and doesn't just let loose

its a spool that holds your bungee cords so you can quickly loosen and tighten the cords once you've got the respected spot tighten the screw on top until theirs no movements but if you do not want to fully down just in case leave i a little loose. I do NOT recommend this for real NVGS more of digital DIY NVS which are lighter than the real things they work better on this spool keep mind of getting your NVGS on the mount correctly if you cant print this if you can not do this (Get your NODS in the correct position on the mount by pushing down then next step do this press the button on the front of your mount back and really push until it wont go back anymore and once you d that simply push your NV onto the mount and once done you should hear a click if you do not continue this cycle until gotten correct) Hope this helped!