npt national pipe thread

an fittings are sized by the amount of sixteenths of an inch. so a AN12 is 3/4 of an inch

when i did mine i used summit racing and the brand was fragola.

when cutting the hose use a tree branch pruner. cuts it as easy as a scissors

Be careful using automotive hose for marine applications. A fire on a boat is not something you can walk away from. I replaced all fuel lines with steel braided hose with AN fittings. It's stiffer and resists wear from vibration. In case of a fire it will take longer to burn through. Hopefully give you enough time to grab a life jacket and hit your DSC button to call the coast guard.