Subdued/Blacked out shoulder flashes

[snake eyes]

Can anyone tell me the history of why elite units military and police swat have blacked out/subdued shoulder flashes/patches on their arm? I know they signify them as belonging to special units but i was wondering how that ever came to be.... Thanks

[SR-25]

So they can hide better...its pretty self explanitory. Why would you run around in camo with a blue and yellow patch on your shoulder?