Two of these came as a "gift" when we purchased our Vitamix 7500. We were excited about it until we took them out of the box. They are SO bulky, slippery, and heavy. It seemed like such a poor design until I came on the Vitamix website and read that they are actually made as personal mixing containers for the S series. This feature makes more sense but as a regular "to go" mug they are just not practical. The only use we will get out of these is for storing leftover liquids.