120 V 230 Volts mains, which is best?

[ppppenguin]

I picked up a handy unit in Poundland recently which plugs into a 13A socket and has two USB ports and a 13A socket.

There is some cause for concern about the USB sockets built into 13A socket outlets which sell for £8 and up. It makes me  wonder how a safe and adequate USB charger can be sold for £1. Or is it one of their few items at rather more. Even at £2 I still don't see how you can possibly make a saef device like that.

Mind you, I've bought Poundland's 3 way 13A blocks and they seem to be OK, at least for light loads.