North Dakota Thin Blue Line Shirt featuring North Dakota with a Thin Blue Line. We print this design on the American Apparel t-shirt because it is the smoothest and softest t-shirt you’ll ever wear. Made of fine jersey, it has a durable, vintage feel. These classic-cut shirts are known for their premium quality, as well as ability to stand up to a washing machine (will keep size and color after many washings). The shirts are 100% fine jersey cotton. Great Police Gift for North Dakota Police Officers, North Dakota Police Wives, North Dakota Police Supporters, North Dakota Residents, and fans of Thin Blue Line Shirts.