The problem is, copper and iron is heavy, and that’s what you’re paying to ship.
I couldn’t find anything on the WWW that looked like the original manufacturer, so it’s going to be hard to find decent information about that device. It’s likely that the parameters will be similar, but that’s an expectation only.
It doesn’t have to be a pre-assembled unit. If you want to do it differently, you could buy an isolating transformer from one of the recognised and reputable component suppliers where you can get all the relevant data, a plastic box for it, fuses and holders for the input and output sides, plugs and leads, and make up your own.