The Bizon is one of those more unusual Russian (Soviet) designs that deserves a airsoft replica, but at the same time is so niche that not many companies would take it on. Luckily Silverback (no, never heard of them) have taken a chance and have made a Bison that looks quite nice...
I suspect that this is a low-run 'Frankenstien' based on something like a Kalash or CYMA (or similar) AKS-74U, but there's nothing wrong with that (my Kalash AKS-74U was fantastic).
At $330 it's a wee bit steep, but if you actually recognise a Bizon when you see one then I'm guessing you are a person of superior tastes and would be willing to purchase this in order to have something a little different. :)
Link: Tokyo Model Company - Silverback PP-19 Bizon-2 AEG