This is the Cormorant V2 which has a patented locking mechanism. Designed by Kizer's Engineer/designer Yue, also known as Doctor_EDC, the Cormorant V2 has multiple opening methods. You can front flip, flipper tab it, spydie flick it with the cutout or use the button lock mechanism. 

Doctor_EDC has put a lot of thought into the Button Lock. He's placed the lock plunge inside the blade to prevent any unintended lock release. The dome shaped lock plunge also allows for a springy feel deploying the knife and control when closing it with the button lock. With S35VN steel (Or the mighty 20CV steel! for the Frag Ti model), this knife not only has great action but performs well on cutting tasks too. 

Overall, this knife has been tuned in well, one of the best budget button locks on the market for sure. 

Check out the FAT Carbon/Elmax Cormorant Here