Wikia

Anti Gravity Hats
Object information
Manufacturer	Weasleys' Wizard Wheezes
Usage	Hat that make the user floats away, ; a prank device ;
Owners	Fred and George Weasley

Anti Gravity Hats was a product sold at Weasleys' Wizard Wheezes in Diagon Alley. A slogan written on the package read "Ruin a gentlemans day by making his hat fly away!", so, presumbly, the hats are supposed to be used as a prank. The Anti-Gravity Hat trick has been around for generations in the Wizarding world, and they are not to be used on Muggles.^[1]