To my way of thinking mason jar ready means you screw on a regular mouth mason jar and BOBS YER UNCLE. But this isn’t that, instead it’s an adaptor that only works without leaking if you muscle it on so it won’t come off, you then screw that adaptor on their regular blender base. Two points of failure instead of one!This method leaves you with a permanent glass jar that only works as good as the plastic one that shipped with regular Tribest blenders. So after years of wishing, in vain, that I could find the perfect solution that lets me blend and use multiple glass jars of which I have dozens, I GIVE UP. No one makes it and I suspect for good reason. The Mason threads and glass lip standard described in a 1857 patent are far too course for any modern manufacturer. The only solution is to either 1) say it has a mason jar that is really only labeled and branded and looks like a mason jar but is sized and threaded just like the manufacturer prefers OR 2) ship an adaptor. Either way, you can’t really use a cabinet full of Classico Pasta Sauce jars, which should fit and not leak.Now let we say this is YAGSB (yet another great smoothie blender) but is not for people like me who wish someone would simply make a blender that has a base that screws on the regular mason jar and then sets directly on the blender.I’m sadly afraid to say that this is a great blender - but that it isn’t natively compatible with the age old mason jar. Wish it was though.