Ventilated trough tray has a solid bottom with ventilation openings (typically 1/4-inch to 1-inch slots or holes). It provides moderate ventilation and better cable support than ladder tray for smaller cables that might sag between rungs. Cable tray (or cable ladder) systems are a popular alternative to electrical conduit systems, as they have an outstanding record for dependable service, design flexibility and cost savings in commercial and industrial applications. Cable trays give cables a clear path. We use different types of trays for different jobs: Ladder. Constructed from high-quality welded steel wire, Cablofil® Wire Mesh Cable Tray is the result of decades of research and over 94,000 miles of installed tray across the globe.