the smaller ones can only thread smaller pipe, where the 12R can thread all the small sizes up to 2",
you could liken it to a 8" adjustable open end wrench, and a 16" adjustable wrench,
the 11R has a different type of ratchet, and die holder, the 12R dies will work with 700 power threader, and the 11R with the 600 power threader,
I think they all take the same die insert in the die holder,
I do not have a 0R or 11R but do have 111R and the 12R (the 111R is in the same category as the 11R smaller smaller than the 12R and only goes to I think 1 1/4" pipe), the unit is no longer made that I am aware of,
some more info at the link below,
Push sticks/blocks Save Fingers
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