blö is a cross between a fan and an air conditioner. It uses a small motor and a blade to create airflow, but it doesn't work like typical fan. It draws air in through a chamber where it passes over peppermint oil which acts as the cooling agent. You don't have to use the peppermint oil, it just enhances the cooling sensation and cools you off much quicker.
The cooler air flows out of the bottom and sides and focuses on a small area of your skin at a targeted location. Unlike a fan that tries to get maximum airflow, blö cools off a small portion on your body using ambient cooling, similar to how an ice cube cools you off. Once that area gets cold, the rest of your body adjusts and you get cooler. When you combine that with the effects of peppermint oil described below you get the perfect combo to cool you off quickly.
You can use it anywhere you want!