Thin Blue Line Men's T-shirt - K9 Black . Our K9 Shirt Shows Support Of Trainers Officers Dogs And Others Who Make Up K9 Units; A Key Element In Protecting Citizens Throughout The United States. Specifications for Thin Blue Line K9 T-shirt - Mens: Manufacturer: Thin Blue Line Apparel Fit: Regular Gender: Male Color: Black Quantity: 1 Package Contents: Thin Blue Line K9 T-shirt - Mens