B-Line Eaton series imperial cable tray and ladder, 6" height, 64.14" length, 42" width, Series 2-5 vertical inside bend, 90°, 36" radius, Aluminum

It is a vertical inside bend, which turns the tray run through 90 degrees toward the inside of the bend, so the wiring side of the tray is on the inner face of the turn. In practice that is the fitting you use where a run has to drop down (or rise) and the cables follow the concave side of the curve. If your run turns the other way, so cables ride the outer face, you need the vertical outside bend instead, not this one.

This fitting is aluminum, which is the usual choice for damp indoor areas, outdoor runs and chemical or coastal environments where plain steel would rust and galvanized coatings get chewed up. It is also the lighter option for long horizontal runs. Steel tray is the alternative where you need higher load capacity in the same profile or where the job spec calls out steel; aluminum will not match steel's rated loading.

Order Eaton B-Line model 6A-42-90VI36. Reading the number: 6 in tray depth, A for aluminum, 42 in width, 90 degree vertical inside bend, 36 in radius. Specify it exactly, since the same width is offered in other radii and in the outside bend version.

The fitting is the bend section itself. Tray fittings connect to adjacent straight sections with splice plates and hardware, so plan on a set of splices at each end plus the hangers or trapeze supports for the turn. Use the splice plates matched to your Series 2 through 5 aluminum tray so the bolt pattern and material line up.