Rothco’s Thin Red Line Flag Travel Mug 1289. Show support for firefighters and fire department with Rothco’s Thin Red Line Flag Travel Mug. This 16oz travel cup has a double-walled, stainless steel insulation to help keep drinks hot and fresh. A US flag with a thin red line is printed on the front of the cup. The cap conveniently screws off and has a flip top for drinking. The thin red line travel mug measures 6.75 inches height and 3.5 inches diameter at widest point. Perfect for on the go, cars or at the office.