I have one of these and I have to say it is the worst cup I have ever owned. The base is so small compared to the height it is extremely unstable, even on a wooden top bench. I've lost more drinks with this thing in the year I've had it. What a mess. The base is so small it rattles around in the truck cupholder like marbles in a cup. Not a very good product if you ask me. Today I am going to replace this piece of junk with a new one....