Take into account that this is for range estimations. All the high speed guys with laser range finders won't need it... Unless their batteries die. Then I suppose they'd just take the batteries out of their Kestrel 4000 and put them back in their laser range finder. I don't know if that would work though, since I don't own either one of those things.
This one is pretty self explanatory. You don't need to speak Russian to figure it out.