It’s hard to put into words just how much better cobalt flatwound strings are compared to their stainless-steel counterparts. It feels like they’ve given me back all the overtones I lost when I switched from stainless-steel roundwounds to flatwounds. And they still keep that flatwound character, but only to the extent that’s actually useful, so the bass tone stays comfortable and mix-friendly in most situations. I haven't checked yet how they will sound in a couple of weeks btw. (Fender Player II Mustang Bass PJ pickups)