This is s sprue of 4mm:1ft scale (OO) cosmetic sideframes to fit to the outside of a 6' wheelbase frame to make Gloucester Fastfreight bogies, such as those fitted to UKF fertiliser vans. The close-up photos are of the same model 3D printed in a grey plastic a few years ago by Shapeways, with similar resolution and properties to the MJP resin grades available from Thangs/Shapeways now.