The PK-AS is one of the most advanced reflex sights in the world. It has a single red dot surrounded by a circle. when the sight losses power the sights red dot and the circle turn black. This feature allows the operator to continue to be able to use the sight even though its out of pore making it one of the most advanced sights in the world.
The sight can be mounted on AK style weapons or even on western style rail systems.