Not sure why you would need a voltage regulator as surely the supply voltage is within certain limits?

Or are you trying to feed appliances from a battery source?...in which case its an inverter that takes 12 or 24v DC supply and produces 230/240v AC from it but this will be at quite a low current so the number of appliances you can run will be limited. The output will be specified in Watts or VA (voltamps).

Alternatively, are you talking about a petrol or deisel engine driven alternator or generator that has no battery input just has an AC output(in the case of an alternator) or DC output if its a generator. If you are wanting to power household appliances then you need an alternator, the output of which will be regulated to give a constant voltage.

Hope this helps a little but i need more information on what your trying to do and what you think these "regulators" on sale in Robinsons claim to do.