12 OZ Stainless steel is vacuum double insulated. The double walled insulated cup keeps your drinks hot and cold (specific time depends on the actual situation), Liner of tumbler will not produce any taste and will not rust. Mouth of the insulated cup is round and does not grind the mouth, suitable for most kinds of hot and cold drinks, suitable for all kinds of drinks such as wine, water, juice, coffee, suitable for home, office, hot tub, beach, picnic or also a nice travel tumbler