Karbonn A21 official Pictures. Karbonn A21 is a Smartphone of karbonn. The Karbonn A21 Android Smartphone. Announced 2012. Features 4.5″ Display, 5 MP Primary Camera, 1.3 MP Front Camera, 1800 MAh Battery, 4 GB Storage, 512 MB RAM. Karbonn A21 price starts.