Calling a product legendary is quite a bold claim, but with Stanleys 110-year history, it's justifiedthis easily recognizable mug has all the makings of a legend. The mugs primary material is 18/8 stainless steel, with genuine vacuum insulation in the walls, and a drinking lid made of Tritan plastic. As is usual for Classic series products, this Stanley mug is purpose-built to take the wear and tear of everyday use. - Keeps drinks hot for 1 hour, cold for 2 hours, and drinks with ice cold for 10 hours - Dishwasher safe - BPA-free