Altman Color Frame
A Color Frame or gel frame is designed to hold color media (gel). Color frames are placed directly outside the fixture, immediately in front of lens assembly. Most fixtures include an integrated holder for the frame. Some accessories designed to mount in the gel frame holder, such as Barn Doors, occasionally include an integrated replacement slot for frames.
Comes in many different sizes for all types of fixtures including, profiles, fresnels, floods and par cans.