The Vacuum double wall was made of high quality grade 304 stainless steel that completely taste-free, rust-proof, leak-proof. The lid was made of food-grade silicone, BPA free, guaranteed high durability. The coffee mug lid comes with an airtight silicone seal that prevents the drinks from spilling. Air Vent on the lid allows beverages to flow out smoothly, without gushing or overflowing. The rubber design at the bottom prevents the cup from slipping or tipping. 12.85oz capacity, small and beautiful, easy to carry. Narrow body design makes it easy to grab and go, also fits most car cup holders and coffee makers.