I have several Sawyer Mini water filters however I wanted to be able to attach them to various accessories and directly to Smart Water bottles while hiking. Sawyer sells a dual threaded version for using accessories so I made an attachment for the Mini to add that functionality.

One is a male thread that mimicks the Sawyer Dual and takes Sawyer accessories and couplers such as Faithhack's adapter (of which this is a remix.) Grab the coupler from Faithhack.

 The other is female thread (remixed threads) that attaches directly to Smart Water Bottles and doesn't require an adapter or coupler.

This is designed to be a tight press fit and may or may not require some epoxy to stay attached especially with a full water bottle hanging from it. Milage may vary based on your printer and water filter tolerances. 

If you need/want it permenantly attached then lightly sand the mating surfaces of the Sawyer outflow end, clean both parts with some IPA, then epoxy in place. Clean excess epoxy with IPA and paper towel.