Dual SIM is now supported by almost all phones. A dual SIM system is provided by all the smartphone companies, although earlier, it was used in very few phones. However, all the latest and current generation models offer dual-sim features like the Oppo A77 4G dual SIM.
The Oppo A77 4G phone is a dual SIM-supported smartphone where you can use two SIMs simultaneously. The phone has two nano-sized SIM card slots. If you want to know more about your phone, you can tell us in the comment box or visit our website.