The Microsoft Lumia 640 is available in both Single SIM and Dual SIM variants, each catering to different needs Microsoft Lumia 640 - Black/Blue/White/Orange - Single/Dual SIM - Pristine Condition. Dual SIM : This variant supports two SIM cards simultaneously, enabling the use of two different phone numbers or network plans (e.g., one for personal use and one for work) without needing to swap SIMs.
eBay