IP = Ingress Protection

IPXX – First digit is rating of protection from solids and dust. Second is water resistance.

X means it was not tested for either solid object or water, not that it doesn’t protect. For instance, an item that is rated as IPX6 means that it was only tested for water resistance. It could potentially be dust tight, but the manufacturer did not put it through the IP test to determine it.

Who does these ratings?

IP ratings are defined by the international standard IEC 60529. Manufacturers cannot assign their own IP ratings. They must go to a certified independent company to get an official IP rating. There are many companies that do this. This is so companies cannot have their own marketing definition of “waterproof” or “dust proof” that’s different from every other manufacturer.