what brake flare tool should i buy

I have NAPA 2199 (Easco, K-D Tools). Insure you get a "double-flare" kit. I have only flared factory steel tubes, and works fine. Some tubing was from newer cars w/ bubble flares (I cut-off), but the 6 mmD (?) works for our 3/16" tubing. Some here mention a better tubing material (nickel alloy) that bends and flares easier. Stainless is harder than regular steel.

BTW, you can make the newer "bubble flares" w/ a standard "double flare" tool. See youtube videos. The trick is to use the flat side of the tube holder and don't do the 2nd step w/ the cone.