Mercury Stepdown voltage converter 230V - 110V 45W

I've had this step-down current converted for a couple of weeks now, and it's never shown any signs of failing, burning or made any loud noise. I've been using it with a 37 Watt air purifier, on and off, sometimes ensuring to not exceed 1 hour usage at a time, but occasionally forgetting about this restriction (read the description and don't use with high wattage appliances). The device does get warm, but reasonably so, like a phone charger. And it does work. How do I know? Well, when I bought my American purifier (120V), I initially plugged it in using an ordinary US to UK plug adapter. The purifier was then very fast/loud, even on the lowest setting, making me think it was broken. But since I started using this converter, the purifier has been working much more quietly/slowly, when expected to do so. It looks like getting twice the current made it work twice as fast, which was not how it was meant to be. Overall, I'm very happy with this product.

Worked for around 5 mins, then got a vibrating noise coming from it , stopped working / cut out , with a strange smell coming from it , possibly overheated , only used on a small aquarium filter, sending back for refund,

This step down voltage plug fit my socket well and is a good weight. Unfortunately I had to return as the item I bought this for did not work.

Using with a 15W load so well within limits. Quiet at first but once it warms up (20min) it makes a very obnoxious and loud buzzing sound to the point at which you can't hold a conversation with it in the room and you can feel vibration if you handle the transformer itself.Worked for about 5 hours total then just died. No noise, no output, nothing.

Its okay it works fine but I didn't realise its only useful for 1 hour at the power rating that I need for my US device

Works well

Used within its limits (45W) this gets the job done. It does hum slightly, which is indicative of a fairly low quality transformer inside it, so how well it lasts remains to be seen.

Buzzed like a possessed wasp. Got immensely hot with only a 4.5w load, then started smoking. Should have taken notice of the reviews as clearly this is a dangerous item and Amazon should be forced to remove it from sale.