Neewer 12"x 12"/30 x 30cm Color Correction Gels Set 4-Color Gel Filter Film Gel Sheet for Video Light Studio Flash Strobe, Set Including: (1) Red Color Gel+ (1) Yellow Color Gel+ (1) Green Color Gel+ (1) Blue Color Gel, This color filter set consists of 4 -12"x 12" gel sheets, (Red, Yellow, Green and Blue) Neewer 12"x 12"/30 x 30cm Color Correction Gels Set 4-Color Gel Filter Film Gel Sheet for Video Light Studio Flash Strobe, Set Including: (1) Red Color Gel+ (1) Yellow Color Gel+ (1) Green Color Gel+ (1) Blue Color Gel, This color filter set consists of 4 -12"x 12" gel sheets, (Red, Yellow, Green and Blue) Made of high light transmission materials with light weight, steady color temperature and low loss Mixing primary color filters are used for experiments involving additive and subtractive color, color mixing, color transmission, absorption and filtering of the different wavelengths of light