Reminded me of kind of an interesting sub-niche. The US military has lots of people overseas, and they pay to move a fairly big amount of people's stuff if the

Reminded me of kind of an interesting sub-niche. The US military has lots of people overseas, and they pay to move a fairly big amount of people's stuff if the service member and their family are moving there. So, there was this cottage industry of huge transformers so that these folks could run their US 110v/60Hz appliances on (mostly) 220V/50Hz mains. Things like microwave ovens, blenders, toasters, vacuum cleaners and so on. They were typically oversized and when you turned them on there was an audible hum and dimming of all the nearby lights for both you and your apartment neighbors. They were also often fairly sketchy steel or aluminum boxes without manufacturing labels. I suspect there were probably some dangerous ones.