I bought the Twister Jar 4 years ago for my mother. It works as advertised but it's durability isn't what I thought it was. After 4 years and many uses, it's starting to leak some small black residue from the gasket into the mixtures. Blendtec said it's pass it's warranty since I bought it after I purchased the Blendtec unit and it's not covered in the 10 year warranty. They did give me coupon code to buy a new one at half price, which I will. Good jar but they need to make them more durable for hard users. And don't worry, she doesn't use it in a commercial kitchen, only home use.