A flag is a device used in lighting for films and photography. It is an object used in a shot to block light, provide negative fill, or avoid light flare from light sources just outside of the film frame. Their usage is generally dictated by the director of photography, but the responsibility for placing them can vary by region, usually devolving to either the gaffer and electricians or the key grip and lighting grips. They are usually several square feet in area and mounted on C-stands or overhead rigs. Most "industry-standard" flags consist of a square wire frame wrapped in black cloth, which minimizes any reflected light and keeps the flag lightweight. However, given smaller budgets or extenuating circumstances, virtually any opaque object can be used to flag light.

The Cage is currently equipped with Flag Kits of two sizes:18"x 24"and 24" by 36".