These Phi Sig stainless steel insulated travel mugs in our Go Sorority design are 20oz skinny tumblers with vacuum insulation technology and BPA free sliders, splash resistant lids and both metal and plastic straws. The powder coated finish gives you more of a solid grip when holding your beverage, plus the vacuum insulation keeps your favorite drinks icy cold or piping hot for hours. We recommend to hand wash these only.