Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Absolutely leak-proof

This is the best coffee mug I have owned in 20 years. It is absolutely leak-proof -- I turned it upside down full of hot coffee and shook it and it didn't spill a drop. I like my coffee very, very hot and it keeps a drinkable temperature for several hours. It fits the cupholder in my car without tipping. It is a great buy; I am ordering another one to have a spare.