Yes, I am endorsed by this great company, but only after I bought several sets and used them. I used to be a long time user of strings in a pink package, but no more. These strings stay in tune, they had a minimal stretching period, are consistent over time and over the guitars I've put them on: Telecaster, Flying V or Les Paul. They last and sound great. Even if I weren't endorsed by Black Diamond, I'd still be a user for life.