In all the documents about them I've seen online these strings are MADE for the U-Bass, acoustic or solid-body and as per a guy I spoke to on the phone from D'Addario in January, he said that they have designed and tested them for both acoustic and solid-body U-bass and other uke-basses made by companies OTHER than Kala...
They tend to be cheaper than the Thunderguts, which I did NOT like, but I have not been motivated to waste another $20 on these and not like them as well (they are using a formula to make them that is licensed/based upon the Aquila Thungergut strings, but slightly different)...
I tend to prefer the black Pahoehoe strings, and have found them to be consistent once broken in.
Having said all the above, I only use my uke basses at home for songwriting and recording, so I have no field experience gigging with them, so I cannot say how the strings might hold up 'out there'...