Slate form factor is the most popular form factor for smartphones currently. They are apt for touch enabled gadgets that usually have very minimal physical buttons.
SIM: Dual SIM (Micro-SIM, Dual stand-by)
SIM or Subscriber Identity Module is used to identify and authenticate a device over a network. They also come with small storage space allowing you to store small number of Contacts and messages. Micro SIM is smaller than Mini SIM. Dimensions: 15 mm by 12 mm.
Android is an Open Source Mobile Operating System by Google for touchscreen devices. Each OEM (Original Equipment Manufacturer, e.g.: Samsung, LG, HTC) can use Android for free and tweak it for their device. There are more than 8 versions till date, latest one being Android Kit-Kat. This phones runs on Android 4.1.2 Jelly Bean.
GPU or Graphics Processing Units are dedicated processors assigned with a task of rendering computer graphics. Faster GPUs give better graphics experience while playing games or doing graphic intensive tasks.
Display type: TFT
TFT[Thin Film Transistor] is a liquid crystal display technology and is good in terms of response and image quality. However this display consumes a lot of power and is expensive. This display is generally considered below average compared to the displays available in market.
Touchscreen: Capacitive touchscreen
Capacitive screens use electrodes to sense the touch of an object that simply has the dielectric value different than that of air. This gives the capacitive screens a slighter edge with respect to sensitivity of the screen. Even a small swipe by the tip of a finger is enough to generate a response whereas its counterpart (resistive touch) requires a heavy touch to get the necessary response.
Pixel density: 133 PPI (Pixels Per Inch)
Pixel density (PPI) gives you the number of pixels per inch of diagnol size. For good clarity (at 100% zoom), minimum acceptable PPI is around 300. Anything lower than 225 is considered below average.