Bought this to replace the nut on my older HB35+. The size was about perfect. Slight sanding on the sides and bottom corners for a good fit. String slots also seem to be perfect. I wanted the high strings' action a little lower, so I sanded about 0.2 mm off that side after careful measuring.
So far, it's been playing perfectly. Has not been long, but I don't expect fast wear or string binding on these.