Storage: 8GB of built-in storage (expanded with a MicroSD card up to 128GB).
Battery: 2500mAh battery (replaceable and is easily accessed when you pop off the exchangeable back cover).
Connectivity: 2G/3G/LTE (microSIM), USB 2.0, Wi-Fi, BT 4.0 and NFC.
Navigation service: Built-in A-GLONASS and A-GPS.
Camera: 8MP unit with f/2.2 lens and 28mm focal length supported by a dynamic LED flash. The front facing camera is a 0.9MP Skype compatible unit. The Lumia 640 supports the popular, convenient Glance Screen feature.
Dimension: 141 x 72 x 8.8mm.
Operating System:Windows Phone 8.1 OS with Lumia Denim (upgradable to Windows 10).
Included Apps: Live Folders, Action Centre, Cortana, HERE navigation and the Word Flow keyboard. 1 year subscriptions to Office 365 (Personal) included.