UltraRail® Series Black Light Fixtures: A Sleek, Modular Design For Small Spaces. Finally, there’s an ultra-cool alternative to the cheap, under-the-cabinet fluorescent black lights you find in hardware stores. For a much more elegant and powerful solution, there’s now UltraRail. UltraRail is perfect for small, intimate, enclosed spaces such as shelving, exhibits, displays, coves, soffits, etc.