The classification level according to the Czech NSA (National Security Office) standard for shredders indicates the level of protection that the vault provides when shredding classified material. The NSA standards divide shredders into several security classes, from NNI 1 (Restricted) to NNI 4 (Top Secret), where each class corresponds to a specific classification level. These classes determine what types of documents can be safely disposed of in a given shredder, with NNI 4 representing the highest level of security for the most sensitive and classified documents. This classification is important for institutions and organizations that need to handle classified information in accordance with legal standards and security requirements.