One comment to the first '5 star review' puts this device at around x8 magnification. I would put it even lower: it is certainly much less than my 10x - and I should have reliased it was a con as I have never seen a 30x loupe (I thought my 20x was unusual enough!).
Also note that there is also a 20x chrome loupe advertised here, and I bought one of each and found them both from the same 'Triplet' brand and both only a tiny fraction of the power described. This is an offence under the Trades Description Act.