1/56th scale US Army WWII Stretcher, also known as a Litter.
This is a 3D printed part, "printed" using the very high resolution sterolithography process. This is NOT the same as the plastic filament process you see in many consumer level machines that create obvious layer lines.
Parts are supplied attached to the support structure as shown in the photos of the unpainted parts. You remove the support exactly as would with plastic model parts on the sprue, use a sprue cutter or hobby knife. Before painting it can be helpful to lightly sand the parts with very fine sandpaper (320-400 grit) to help with paint adhesion ,,, this is recommended but not required.