Just wanted to share a recent experience with Wolff. I ordered a spring set for an old WWII era pistol and though what a great time to get some extra power hammer springs for my H&Rs - and save on shipping. Without checking here, I assumed "double coil" is better than "single coil" - LOL. So the joke was on me, modern Handi hammer springs are single coil.
A quick email to Wolff explaining my mistake and they shipped a replacement order ASAP and a return label for the exchange. Got to love that type of customer service!