DURAN® blanks for flat flange covers can be further processed into customer-specific articles using further DURAN® components (threaded tubes, standard ground joints, threaded sleeves, etc.). Due to their geometry and solid wall thickness, DURAN® flat flange covers are pressure and vacuum resistant. For pressure resistance, please refer to our notes in the technical appendix of the laboratory glassware catalogue. For glass articles which deviate from the original form due to further processing, the permissible operating data must be determined in accordance with the technical rules and regulations."