Like many of my designs, it offers both a slouchy and a beanie version.
The main color is a chunky-weight yarn -- here in Loops & Threads Charisma in Charcoal and Wool-Ease Chunky in black. For my sample hats, I used two strands of worsted weight for the contrast colors, but one strand of chunky would be good, too.
The three-color stripes were inspired by British regimental ribbons, often worn on Panama hats.