This product has literally saved my kitchen from smoothie messes while using my Vitamix. I make green smoothies on almost a daily basis and one day during blending I had smoothie spewing out from the blender container. I didn't know what had happened and was worried that I broke my Vitamix. After contacting Vitamix I was told that the bolt/nut that hold the blades in place had most likely come loose. They offered to send me above wrench to help tighten the bolt for FREE. I tried to tighten the bolt by hand but couldn't get it tight enough. The wrench fits perfectly into the bottom of the Vitamix container and allows you to tighten the bold much tighter than can be done by hand. The bolt gets loose after a lot of use with the Vitamix because it is blending at such high speeds. Every once in awhile I remember to tighten the bolt with the wrench and it has quite literally saved me from more smoothie spraying all over my kitchen. Thank you Vitamx!