Zojirushi SX-DA45 Tumbler, 15 oz/0.45 L, Stainless Steel Stainless steel vacuum insulated tumbler Stainless steel vacuum insulation keeps the outside of thetumbler from becoming hot when filled with hot beverages,and prevents condensation when filled with ice coldbeverages Stainless steel vacuum insulation also minimizestemperature change, keeping hot beverages hot and coldbeverages cold SlickSteel polished stainless steel interior is easy to clean 2-3/4" wide opening makes cleaning easy