Steel copper Tumbler set of 6

Capacity- 150 ml each
Material- steel exterior. Copper interior
Health Benefits of copper- Aids Digestion, removes toxin for digestive system, Maintains bone density, . Copper has anti-microbial properties that aids in water purification (Click to read article)
Together with iron, copper enables the body to form red blood cells. Low copper levels have been associated with high cholesterol and high blood pressure. 
Precaution- Never store or drink acidic (lemon orange) or alcoholic drink in copper, it may cause severe adverse-effect.