ECCN is an acronym for ‘Export Control Classification number’ and is a US term. Although all export control regimes operate under the same base document the US does have some additions/divergence from the main Wassenaar list. For example numbers starting 5A9 will not be recognised in the EU as a decontrol as it does in the US. You then need to be aware that the US decontrol may not have the same effect in the EU. You can find more out about ECCNs or Ratings as the term is in Europe here -