"Cirkul" is a brand that offers a water bottle with replaceable flavor cartridges. The product has received mixed reviews from customers. Some users have praised the product for its convenience and variety of flavors, stating that it has helped them increase their water intake. However, others have reported issues with shipping and customer service. It's always recommended to do thorough research and read multiple reviews before making a purchase. Please note that this information is based on available online reviews and may not fully represent all customer experiences with "Cirkul".