Most of the ARCHOS devices allow to insert two SIM cards and a micro SD card simultaneously. Consult the quick start guide to identify each slot and insert the corresponding card.
However, some devices do not allow you to insert two SIM cards and a micro SD card simultaneously.
You have the following options:
1° A SIM card + a micro SD card
2° A SIM card + a SIM card
The SIM card size can be mini, micro or nano.
Refer to the quick start guide for more information about your device's possibilities and the card size adapted to each slot.