I recently put a set of D'Addario Chrome flats on my RB-5 (I'm a flatwound lover). Well, all was great except for the B-string. It had some weird harmonics and just in general sounded muddy. The rounds that were on there before were as clear as you could want. I took the bass to my luthier to check it out, make some minor adjustments and see if he could find the problem with the string. Nope. All was well with the bass, but he couldn't get the muddy sound and harmonics out. So, I returned the string to D'Addario to have them evaluate it and send me a new one. I was simply asking them to replace the "B", not the set. Gentlemen, and Ladies, they sent me a whole new 5-string replacement set, FREE! I gotta say that it was far beyond what I expected. I had heard they were good to their customers, but this was just great. I haven't put the new strings on yet, but will tonight. I'll report back as to how well they worked.