NIU Niutek 3.5D2 official Pictures. NIU Niutek 3.5D2 is a Smartphone of niu. The NIU Niutek 3.5D2 Android Smartphone. Announced Aug 2014. Features 3.5″ Display, MT6572M Chipset, 2 MP Primary Camera, 1200 MAh Battery, 2 GB Storage, 256 MB RAM. NIU Niutek 3.5D2 price starts.