One of a few solutions to make the gun California Compliant™. This fake silencer makes the barrel long enough to get the overall length a bit past 30". It functionally does nothing.
The Meprolight red-dot looks funny up there, but that is how people install glass or reflex sights on these bull-pups.
The California Compliant™ absence of the pull-tabs that release the magazine require you to jigger a long object in there and pull the retaining wedge back yourself. Then the long magazine pops upward.