I fit this to a Woom 4 (easy, almost a direct fit, had to bend very slightly) and Woom 5 (less easy, because no front crown bolthole; had to put in a 90° bend in the horizontal support to meet the under-crown bolthole). Very ductile steel, which . . . good for bending it to the shape you want and fitting to various bikes, but probably less strong than higher-carbon steels. Seems likely to be strong enough for most ordinary purposes though. All the labor (welding, painting) look to have been skillfully done. Shown here with Ikea Sockerbit as basket.