Vintage Exposure Value Cards
At one time, Kodak included with its Pony II camera produced from 1957 to 1962, small exposure value cards. Kodak also included these cards with some popular consumer films like Kodacolor, Ektachrome, Kodachrome, Plus-X, Pan-X and Tri-X for a period of time in the 1950s and 1960s.
The cards were intended as a handy aid for the photographer and were meant to be placed in a small holder on the back of the camera (the film door).