These tumblers are 16 ounces and made of stainless steel with proprietary triple insulation. They keep your cold drinks cold for up to 9 hours and your hot drinks up to 3 hours. Even in the sun these tumblers keep your keep nice and cold with no sweating or freezing. They feature easy grip sides, no slip bottom, are shatterproof and are stylish for spill free sipping all day. Add a monogram and your good to go!