Dual shell helmet for minimizing rotational acceleration

A helmet comprising a first shell defining an inner cavity operable to receive a head of a wearer and comprising an outer surface, a second shell comprising an inner surface and an outer surface and defining an inner cavity, the inner cavity of the second shell containing the first shell, the first shell comprising at least a first dampener disposed on the first shell outer surface, the second shell comprising at least a second dampener disposed on the outer shell inner surface, wherein the first and second dampeners are positioned between the inner and outer shells and wherein one of the first or second dampeners is rotatably engaged within an opening formed in the other of the first or second dampeners and wherein the engagement of the first and second dampeners facilitates rotational movement between the inner and outer shells upon an impact incident on the helmet.