So it's just a four-way mains board, yes? Maybe not 'just'... Clearer Audio manages to produce five pages of description and specifications, which go at least some way towards justifying the price.
For a start, it is made of quite thick steel, robustly screwed together and fitted with good-quality unswitched sockets. It is fitted with a thick, short cable terminated with a very funky plug (also used on Clearer's mains cables, a handful of which were supplied to us to use with the Hub). The one downside is that the cable is sufficiently stiff that it can be hard to rotate it to fit into a socket.
Inside the Hub, the extra-thick wire theme is continued with star connection of each socket to a seriously chunky terminal block, and some very simple filtering is provided in the shape of a ferrite sleeve over all the cores of the main cable just as it enters the housing.
There is also a little group of spike suppressors. In terms of filtered versus unfiltered mains boards, though, this is in the 'un' category: it is basically all about good-quality copper, connections and construction rather than mains cleaning.
We used it to feed a couple of systems, one distinctly upmarket and one quite middling: the former system already had slightly tweaky mains cables in use, fed from multiple wall sockets. Perhaps surprisingly, we heard a difference with each, but in all honesty it was far from night and day.
With the Hub replacing just three of the four wall sockets in the upmarket system the sound seemed just a shade cleaner with 'blacker' silences, while in the middling system, replacing a B&Q four-way, the Hub seemed to allow a little more room for stereo images. But in value terms? We'd put money into interconnects or speaker wires first.