Yeah it´s solid in both senses of the world. I think it´s about 8 kg.
It´s the only proper way of attaching a kid´s bike to the towing machine that´s worth considering. Very well designed and built. It essentially turns two bikes into an articulated tandem.
The kid´s bike is very easy to attach and release and the same goes to removing the whole thing from the towing bike. What we used to do when the kids were smaller was ride to daycare and then I´d leave the Follow-me Tandem with the kid´s bike attached there.
I got ours from a flea market in Brussels for the princely sum of 1.5 euros. Was practically new.
If you have small kids get one at once.