I use a cheap USB power meter, but came across this one that can ID the device for things like telling if an Apple charger is real or a fake without taking it apart. It's the ChargerLAB POWER-Z KM003C and much cheaper on Aliexpress for $70 plus some other discounts on it. Not sure if I'd use it though, I buy the Samsung ETA0U60JBE chargers, which measure just as well as the Apple ones at $10 for a five pack with shipping from a cell phone recycle store. Just seems so cool to identify things as well.