I am not certain if you have a SC51 or SC50. One has strobe if I recall correctly. There was also a SC50w and a SCw+ again I may have it all wrong.
I have a SC52L2 so what do I know?
Zebra can be simple HML. It can also be a little more fussy. High can have a sub level as can Medium and Low. Essentially you can have 6 levels. IF yours has strobe then 7 options.
My light can take a mix of cell chemistries. I am not sure if yours can.
It took me a while to differentiate the models when I was looking into ZL.
I sure hope I didn't make a mess of this

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Someone more knowledgeable like NutSAK can help better.