Rothco Deluxe Acrylic Skull Cap 5566. The Rothco Deluxe Skull Cap is made of a lightweight material that is warm and comfy, making it the ideal cap for chilly weather. The acrylic material helps keep the watch cap’s shape and color while also providing warmth. For working outside, such as shoveling snow, the beanie cap is great to wear. The cold weather cap is perfect for everyone since it comes in a variety of colors and is designed to fit most people.