My wife brought home these cups from Costco today. Three for fourteen bucks or something. I didn’t think much of it until I took one, filled it with ice and water, took it out to the deck and sipped it. Quickly I realized that this was no ordinary cup I was holding. Upon closer examination, I noticed the cup was made with double wall so no condensation forms outside and the double wall keeps the drink cold longer. The entire cup and straw assembly is made from a very sturdy BPA-free plastic, so it says on the label. I have no idea what BPA is, but it sounds very dangerous and something I want to stay away from. No BPA for me with this puppy. The straw has a little ridge at the bottom end to keep it from sliding out. I hate it when my straw suddenly flies out. Let me tell you, the straw in this cup is staying put. No accidental straw extraction here. The inside of the lid is lined with a rubber gasket so when you twist it shut, the cup becomes pretty much spill proof. This is like a sippy cup for grown-ups. Ingenious.