Hi,

Khukris and Gurkha hats are part of the ceremonial uniform of the Gurkha Rifles (or Gorkha Rifles, as they are spelled in India); as well as the Assam Rifles, which is a paramilitary force.

The Gurkha hat, alone, is also worn by the Kumaon Regiment, the Garhwal Regiment, the Assam Regiment and the Naga Regiment.

Hope it helps.