Ken Shirriff, from his blog:

A reader sent me a charger he suspected was counterfeit. From the outside, this charger is almost a perfect match for an Apple charger, but disassembling the charger shows that it is very different on the inside. It has a much simpler design that lacks quality features of the genuine charger, and has major safety defects.

Great teardown, complete with detailed pictures. Astonishing how realistic a counterfeit Apple product can be.

[Via MacRumors]