The Navalock container lock provides the option to securely seal container freight. A visual inspection at each intermediate station of the container enables determination of proper sealing of the container and prevents unauthorized opening of the container during transport. Two steel bars, connected with a numbered container seal, fasten both container doors such that opening or levering a single container door is impossible. In the standard use of only a single container seal, it is more and more frequently the case that the container doors are levered open without damage to the container seal, without it being visually recognizable. Evidence of theft is then as good as impossible. The destruction of the Navaloc, e.g. through the use of a prybar, bolt cutters or with cold spray, is impossible due to the use of iron composite materials and the strength of the material. The container can only be opened by removing and replacing the numbered container seal, which can be determined at every interface by comparing with the seal number in the transport papers.