I think they use arctic char. (Ooh, another great finish for Glen Googly.)
I don't believe that Scotch distilleries use degrees of char in the same manner as bourbon ones. To my knowledge, they only char casks after they scrape them out prior to a fourth of fifth fill, in a last attempt to get a bit more use out of an old cask. I can't say I'm 100% certain about that, and invite correction (oh yes! I've been a bad boy!). In any case, I've never heard of them talking about levels of char in the same way bourbon distillers do.