Transit Collection with AeroLight technology is engineered to be light, packable, and leak-proof for the trail or the daily commute. These commuter-friendly Transit Mugs are 33% lighter than Stanley's standard stainless-steel metal drinkware. The collection is built with Stanley's AeroLight technology, which consists of spun-steel, double wall vacuum insulation to reduce weight - without compromising hot/cold retention or durability. These fully leak-proof mugs offer a streamlined design and low-profile lid, compact and easy to carry. They also fit comfortably in car cup holders.