Secure, digital memory cards that use flash-type storage (non-volatile storage). Their special shape protects them from wrong insertion into the card slot. A lateral device for write protection (sliding switch) protects them from accidental deletion of data. SD cards can store up to 2 GB (SD 1.1 standard) whereas SDHC cards can store up to 32 GB (SD 2.0 standard). SC-XC cards can store from 32 GB to - theoretically - 2.048 GB (SD 3.0 standard). Information on recommended memory cards can be found in the Internet (see Auerswald: Auerswald Service Portal, FONtevo: FONtevo).