What is this prototype?

Nowadays,I found that someone is selling this kind of TI-Nspire Prototype online.I have checked out the Tiplanet prototype gallery,but no any prototype picture looks exactly like this one.
This calculator looks both like Phoenix and Nspire CAS+,however,there is something different,for it's letter keys are in the color of green,and it has a independent [approx] key on the right-bottom of the keyboard,and it got no name.
This calculator looks both like Phoenix and Nspire CAS+,however,there is something different,for it's letter keys are in the color of green,and it has a independent [approx] key on the right-bottom of the keyboard,and it got no name.