The Nokia Lumia 635 AT&T Black Smartphone RM-975 is a quad-core smartphone with a 4.5-inch screen and 8GB storage capacity. It runs on Windows Phone 8.1 and has a 5.0 MP camera resolution. With a single SIM card slot and network locked to AT&T, this smartphone offers Wi-Fi, Micro USB, and USB 2.0 connectivity. The sleek white design, microSD memory card type, and without contract make it a versatile and reliable choice for users looking for a dependable mobile device.