International Protection (IP) is coded to represent the level of protection of the assembly. The coding is as follows:
If an assembly is tested for both protection against foreign objects and water ingress, it will be given the code for the two representative digits e.g. IP43.
Where a number of assemblies from the same range are being tested, only one representative sample shall be tested if they share the same build construction.
Watch IPX4 testing video here.
See also Internal Form of Separation page.