Iron Flask Narrow Mouth Bottle with Spout Lid, Sky, 32oz/950ml. Our functional and stylish 32 oz Classic Tumbler is made with non-toxic 18/8-grade stainless steel and double-walled vacuum insulation, so you know your favorite drink will stay cold for 16 hours and hot for 4 hours and will never sweat, have a metallic taste or create a funky smell. Every tumbler cup is finished with a powder-coating, so you know it will look out-of-the-box long after the drops, spills, and whatever else befalls it. Plus, we’ve added two stainless steel straws and two plastic straws to your box, as well as two straw cleaning brushes. Sip, sip, hurray!