They were designed in the 1970s came to our attention in the 80s when Rotosound Round wounds were the string of the day. Most recordings on a Wal were made with them on and that's how their reputation was forged.... however, times change and since Pinos flat wound bass playing influenced Voodoo album appeared, over 20 years ago, flats seem to be the go to and won't chew the frets or neck up as much....love flats, tapes and rounds on my basses ....= buy 3 Wals 🤣🤣🤣👍