It's certainly big enough for a normal sized standard ukulele. But when I bought it there were no measures, and I actually bought two with the intention to also have one for my bass ukulele (which is slightly bigger). But the neck didn't fit, so I now use the extra one to hang a microfibercloth, a bow in a bow case, and some extra cables when one stage instead. Whereas the bass ukulele goes upside down in a guitar holder instead.
Stable metal construction, haven't had any problems with the attaching part either.