As a metal sculptor, I have found that many welding supply stores in my area do not stock solder flux. Some stores only sell flux coated soldering irons. I prefer uncoated rods and control the amount of flux I use and am very happy with this product.
I had a crack in the base of my drill press, it was a big crack and the base is cast iron so I decided to solder the broken parts together I had a rod to Solder but there was no flux so I found it on Amazon for a good price and it worked fine for me.
Product was delivered very quickly. The jar of granular flux was well labeled .and best practices.I bought this type of flux because I didn't want to have a pasty flux that would sit around, dry out and be thrown away after a single use.Also a great price.