The glengarry bonnet is a traditional boat-shaped hat without a peak made of thick-milled woollen material with a toorie on top, a rosette cockade on the left, and (usually) ribbons hanging down behind. It is normally worn as part of Scottish military or civilian Highland dress, formal or informal, as an alternative to the Balmoral bonnet (or its less formal variant, the tam o' shanter). Among Scottish regiments, the glengarry is by far the more popular uniform headdress.

Classic Glengarry wool cap with Dicing

Glengarry caps are a military invention of the early 1800's. They were not adopted for regulation use until the late 1800's. The dicing band around the base indicates loyalty to the House of Hanover.