I have found that the cheaper brand double flaring tools are junk. They do not grip the tubes tight enough and they "walk" out of the "die" when you are trying to flare the tube. :violent1:
Spend the money and get a professional brand one; Snap-On, Mac, Etc. :thumleft:
They work much better and are worth the extra money. Believe me, when you are trying to flare the tubes and it keeps slipping down the tube instead of flaring the end, you'll wish that you took my advice.... :banghead:
I bought a snap-on and have been much more successful with my double flares. :D