Clarify differences between Stanton 980/ 981 .

I have a Stanton 980 HZS with the D98 stylus which has never been used. I mounted it tonight and am intrigued by the sound. What EXACTLY is the difference between the 980 and the 981? About the HZS and the LZS, I have the impression that the difference lies in the resistance(Z) that they like to be loaded at. Do I have the right impression or is there some other reason for the HZS/LZS designations?

Thanks in advance for the replies.
According to my book there is a differnce in output.

LZ shows a low output of .3

HZ shows output of 3.5

Is this correct?

My Collector's Series 100 output is 3.2
Hi Rrog,
L is low and H is high output. The difference between a 980 and 981 is the 981 came from the factory with a matched stylus. The bodies are the same if the output is.