I bought these so I could use a bow on my fretless bass and they work really well, totally performing as I had hoped they would. The tone is deep and bright and the strings have a good feel in general for normal play aswell - I prefer them, certainly for fretless, for all play.
Roundwound strings, which my bass was fitted with prior to stringing with these, are not good for bowing and sound "just wrong" when you try. They also bite through the bow hair a lot quicker. In contrast, these flatwounds really work well with my cello bow. (don't get confused, I'm still talking about my fretless bass but I use a cello bow to play it with, I'm not all of a sudden talking about a cello)
These are good, strong strings that hold their tone for a sensible amount of time. Certainly recommended for fretless bass playing of all kinds in general.