California Code of Regulations Title 11 Divison 5 Chapter 39 Article 2 Section 5471
(r) “Flash suppressor” means any device attached to the end of the barrel, that is designed, intended, or functions to perceptibly reduce or redirect muzzle flash from the shooter's field of vision. A hybrid device that has either advertised flash suppressing properties or functionally has flash suppressing properties would be deemed a flash suppressor. A device labeled or identified by its manufacturer as a flash hider would be deemed a flash suppressor.
(r) “Flash suppressor” means any device attached to the end of the barrel, that is designed, intended, or functions to perceptibly reduce or redirect muzzle flash from the shooter's field of vision. A hybrid device that has either advertised flash suppressing properties or functionally has flash suppressing properties would be deemed a flash suppressor. A device labeled or identified by its manufacturer as a flash hider would be deemed a flash suppressor.

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