I have been using Karboon A21 from quite some time, though initially I was very impressed with the online review of this phone, however when I started using it is when I actually knew about it.
It as heavy phone with a metallic body inside, the headphone which has been provided with the phone is an old technology rather than in the ear headphones which are provided with all the leading phone manufacturers.
The radio and the music player sound is cr@p.
The phone start to heat up during long conversation and during charging.