Tubing Flaring Kit Double Single
Product Review (submitted on October 8, 2009):
Depends what material you use. I buy a quality line from a local vendor, mild steel made in germany, have similar flaring set (a cheaper one from harbor freight) but so far have not had a single leak. Make sure you have a nice flat, lubricated cut. If you have a strong fingers yet cannot shape the line by hand then the steel is too hard.