When working with hose and tubing, it helps to have choices. If you had time, you could research all the fittings available, and choose wisely based on everything you've learned about:

Compression... Bite... JIC Flare... Face seal... Grab ring... Metric...EO... Pipe... Straight thread... Flange... Swage... Weld... Solder... Braze... Push-to-Connect... Sweat... Flareless... Sanitary... 1 1/4 turns....1/4 turn... 1 3/4 turns...Torque... Finger tight.

...And after you have had the time to learn all about:

Steel... Brass... Stainless... Nylon... Polyethylene... Polypropylene... PVC... Teflon®... Copper... Hastelloy... Aluminum... Monel... And so forth.

...Or save yourself time and lean on Quest Engineering to solve a problem with tube fittings...so you can turn your attention to other decisions that need to be made.