Not much about this tool.
Materials are simple: RHS Aluminium at desired length; aluminium tube size to suit comfortable grip, some flat copper with edges formed to avoid injury and some rivets or panhead self screwing screws. easy peasy ineal for cheap skate unless you have to buy a full length of the rhs but a few diff length screeds could be made.
For a very long screed two handles can be easily attached allowing a guy at each end to screed the concrete or soil.
Just sold this one after many years of use. Now I can celebrate with a beer LOL. No more sore back for me!