SIGN SCHOOL XING SYMBOL 30x30 .100 ALUM B/FYG DG S1-1. This sign is perfect for signaling the area that is no longer considered a passageway for cars. With an eye-catching design, it's visible up to 1,500 feet away at night, thanks to its diamond-grade reflective aluminum. Plus, its protective film keeps your traffic sign looking even brighter.