The phone runs on Windows Phone operating system. Has a processor Qualcomm Snapdragon 400 with 4 cores at 1.2 GHZ. Comes with 1 GB of RAM, 8GB internal and is expandable with memory cards up to 128 GB.
IPS screen 5 inches with a resolution of 1280x720 px, protected by Corning Gorilla Glass 3. The battery is 2500 mAh.
Size 141.3 x 72.2 x 8.8 mm, weight 145 grams
Reset to factory settings for Lumia 640 is performed as standard for the series Lumia:
Turn off the phone
Hold down the "power"
After activation of the vibration, release the button "start" and quickly press and hold "Volume -" until the appearance of an exclamation mark
Click "Volume +" "Volume -" , "Enabling" and then "Volume -"
The phone will reboot and on the screen you will see the gears, indicating a well-executed combination. After loading the phone settings will be reset to the factory default and will erase all user information.