The bombilla or metal straw included is bronze with a nickel plating bath. The mate or gourd has gone through a deep analysis of use, and innovates in the system through which it empties. Does not fix tastes or odors (hence different flavors and sweeteners can be added). Does not allow bacteria to fix. The material is thermic, so it keeps the temperature of the yerba mate without heating the hand. It’s flexible and unbreakable, hence easy to carry around. Dishwasher safe!