Copper Nickel pipe ..........assortment of threaded ends..........and this tool:
( tool maybe rented at no cost at the local parts store. The flare tool pictured is particularly good and making perfect flare every time. To the point it’s almost fool proof with nickel copper) It’s not dirt cheap and sold under few different brands and or names.
All the lines should be replaced if one failed ??????? If not carefully inspected ??????
