I got the Maxima at an autoparts store, I am not sure if Napa carries it. Just call them and ask. And yes it is Maxima Blue in a tub. I locked the diffs in my T-maxx with silly puddy but if you want the diffs to work as diffs are supposed to in the future then silly puddy is a PITA to get out. I think a tub of the Maxima set me back about $9 USD. Not a lot when it will last a LONG time.