It's a simple funnel.  Pretty thick and sturdy, probably more than normal people would want, but I was tired of trying to fight with the funnels people use to put glycol in their RVs.  I made this to stick right in the hole for the RV fresh water, and I just dump glycol right in, have the pump pull it into the lines, and boom, all done!

PLA, PETG, whichever you want.  Happy to send the fusion files if you want them.