Asus Zenfone 2 was launched in March last year. It has a 5.5 inch display with a resolution of 720 x 1280 pixels. It is powered by a Intel Atom CPU which is clocked at 1.8GHz and has 4 cores. The rear camera is 13MP while the front camera is 5MP. The internal memory of Zenfone 2 is 16GB and it has a microSD card slot.
Asus Zenfone 2 runs on its own custom UI. If you are not a big fan of it, you can install CM 13 ROM running on Android 6.0.1 which is almost as clean as stock ROM. A detailed guide on how to install CM 13 ROM is given below.