Hello kind plumbers.

I have been struggling to figure out what fits onto this pictured brass fitting that will allow it to connect to a 1/4" plastic water line. I have tried a variety of fittings and none seem to work.

I assume I need a push to connect fitting like this one, but the two I tried were unable to screw on.

• Female Straight 1/4 Inch Tube OD x 1/8 Inch NPT Thread Push to Connect Fittings PCF-1/4-N1 was just a tiny bit to small to screw on, it seemed like the correct size but maybe a different thread besides NPT? Maybe it needs to be a compression connection? I honestly have no idea just what I saw googling.

• The second part of this item was able to screw on (Proline Series 3/8-in x 1/4-in Compression Adapter Fitting)But the issue is it was not watertight and leaked like a sieve, do I need some combination of brass compression adaptor and sharkbyte push to connect?