Why is this a favorite? It is just a glass container.
This tumbler is at the ready for me wherever I am working. So why? I love using glass and this one is sturdy. The bamboo lid fits securely, with a better seal than any other I have used. (And it is BAMBOO, sustainable, beautiful and of the earth.). The straw is so easy to clean and accommodates other goodies l love to add to my diet like chia seeds, psyllium and flax seeds.