It's powdered in the container (can't remember if this is how it came or not?).
I have an older container of ITC 100 (1-gal?) that is dry powder like yours and was unsure of it coming like this in the past since I've only seen it wet. It's from our old Tech's supplies from who knows when (container/label looks at least 10-15yrs old). The last time I bought some myself it came wet just like any kiln mortar or IFB cement and there were no options for a dry version. I asked a few companies and everyone I've always asked said it only came wet even though the label specifies to "add water and mix well" (so I can only assume this is how it "used to come" many years ago). I have not called up ITC to confirm this though.
I know a local who coated his gas kiln with ITC 100 and it reduced his ^10 firing time by at least 2hrs. I'd say the stuff works IMO.