Best roundwound bass strings in my opinion. They have the growl and midrange complexity of the Rotos without the scratchiness. They also don't eat up the fingers like those do. Then you get the supple feel and bright chimy highs of brand new D'Addarios, only here it stays longer. In fact, these are - in my experience - longest lasting un-coated roundwounds. Of course your body chemistry and playing or hygiene habits may vary. I, however, never got so much mileage. Even when they die out a bit, the tuning stability and pitch clarity remain excellent, only the higher end get muffled, obviously. Can't recommend them enough. Compared with what I've used extensively in the past, in order of familiarity:
D'Addario XL
Rotosound 66
Dean Markley
Ernie Ball
DR
Hartke
etc
and then flats, tapewounds etc