Posted By:
MikeU"Mike- they now have the 1910 T212 Obak Series of 175 listed but not the series of 150. The 150 series has cards with different fronts than the 175 series (many are the same) but all backs are different. This isn't a situation similar to the T206 set where all the Uzits comprise a subset or in the T207s where all the Cycles are a subset, this is a totally different set.
tbob"
I think they meant the one registry to cover both sets. Here is the comment they have for the set.
"* Indicates a card that exists with both "150 subjects" back and "175 subjects" back"