Buyers Products 30 Inch Stainless Steel Light Boxes with Mudflap Mounts work with 4 in. round, DOT-approved lights for municipal salt spreaders. The versatile boxes also feature integrated brackets that make it easy to mount your mudflaps. The light boxes are made of polished 304 stainless steel with a spring-loaded design that helps protect them from impact. Driver- and passenger-side boxes can be ordered individually or as a set.