The vacuum double wall was made of high quality 304 stainless steel, rust-proof & leak-proof. The lid was made of food-grade silicone, it?s easy to clean and has an elegant appearance. 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. It has an LED temperature display on the top of the thermos. Easy to understand the internal temperature of the liquid by touching the LED screen. No need to test the temperature by mouth and avoid burns.