Yes, the Cirkul water bottle is legit. The Cirkul water bottle is a real product made by Cirkul Inc., headquartered in Tampa, Florida.
However, Cirkul has received a number of complaints and was given an F rating by the Better Business Bureau as of April 2021. So while Cirkul is legit, their customer service leaves some parched.
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Cirkul
A water bottle that customizes the flavor of your water