The lid is made of food grade silicone, it is safe, non-toxic, which is adequate for the rim under 10cm. 

Cold and heat resistant silicone from -20 degree celsius to 120 degree celsius. 

Press the cute figure design to make the lid stick to the cup tightly and isolate the dust.

It is fade-proof, anti-slipperiness, dust-proof and washable. 100% eco friendly silicone, which is easy to clean.