Does the lid of Xi Shi's mug come off easily?

The lid of Xi Shi's thermos cup doesn't come off easily. Xi Shi's innovative patented temperature lock ring for the thermos cup, the hot air is not easy to leak, and the heat circulates internally, so the baby will not bite and suck, and his lips are attached to the V-valve, so he can automatically open his mouth and drink freely. Patented V-valve can prevent leakage. A vacuum cup is a water container made of ceramic or stainless steel with a vacuum layer. There is a cover on the top of it, which is well sealed. Vacuum insulation layer can delay the heat dissipation of water and other liquids to achieve the purpose of insulation.