Early buffalo plaid shirts were constructed of cotton flannel, and that style remains popular today. Flannel is warm, soft, easy to wash and comfortable—everything you need in an outdoor shirt. But other materials are also popular. Wool buffalo plaid shirts have been popular with hunters for many decades, especially in the woods of the northeastern United States. While not always as comfortable as cotton without wearing an undershirt, wool plaid shirts perform better than cotton when wet, so are often the top choice when going out in inclement weather. Shirts made of wool blended with nylon or polyester are also very popular, often more comfortable than 100 percent wool shirts and also excellent in wet conditions. Still other buffalo plaid shirts are made completely from synthetic materials like polyester.