Aluminum Diamond Plate on Top & Front. Includes Steel Catch & Fasteners for Rubber Holddown. OEM STYLE EXTRUDED STEP. Fits Peterbilt 389 379 385 377 378 357 and others. Meets and exceeds OEM Quality, Strong, tough and well built. For custom orders or questions contact me. The Cover measures 15 3/4″ – 30 13/16″ wide -16high overall.