Also called groundwounds. Does anyone else use these? They're near impossible to find (at least in Missouri) so I don't get them that often, but I love the sound. The strings are normal roundwounds that have been ground down to feel like flats, but still have brightness. I'm also apparently the only person in the state who's heard of them. 9 out of 10 salespeople at music stores, and 4 out of 5 bass players have never heard of them.