The test consists of 15, 2" x 2" (5 cm x 5 cm) red, blue, and white plastic chips designed to help parents, teachers, and doctors assess children’s visual difficulties in twilight. The test situation is not a formal test of night vision, but gives useful information on visual adaptation to lighting changes.

https://leatest.com/sites/default/files/pdf/252900_ConeAdapt.pdf