I was using a Nutribullet because I need a fast, easy to clean solution for making smoothies on the run. When I found out there was an adapter blender for the Vitamix I ordered it right away. At first, the blender seemed too tight and I had some struggle to unseal after I mixed a smoothie. After one or two uses, it now securely holds the to go mug, but it can be unsealed by hand, no tools. Very sturdy containers, double walled. Very easy to clean, I just rinse the blender part with a hand sprayer and set to dry. Now the bullet is no longer cluttering my counterspace.