Threat Advisory warning signs from Uticom Systems Inc. make for highly visible, easy to change postings of current National Homeland Security alerts regarding terrorist threat levels. Made of 1/8-inch thick Lexan, the signs are highly weather- and sun-resistant, as well as easy to clean. Five interchangeable panels correspond to the NHS Advisory System color-coding of threat levels: green for "low;" blue for "guarded;" yellow for "elevated;" orange for "high;" and red for "severe." These are available with text that either identifies the color or the threat level. Main sign standard size is 14 inches by 21 inches, but practically any other size may be ordered.