I needed a 120v to 12v transformer, so I found these small DL 60 transformers on ebay. I hooked them up and turned them on, measured them with my DMM and got zero volts. I looked all over for documentation, couldn't find anything. Finally, I thought perhaps it needed a load before it would turn on. I hooked up a light bulb and lo and behold, it worked. So I measured the output and it still showed zero volts. It finally dawned on me, these weren't transformers at all, but switching power supplies! My meter read zero volts because it is expecting 50 or 60 hertz, not switching speeds. Can't manufacturers label what their devices actually are?