As explained by Clifford Mishler, the World War red and blue OPA (Office of Price Administration) tokens in this picture (I have these two of them), that were produced in 1944 or 1945, "are of a sandwich-type fiber construction, consisting of a red or blue outer layer bonded to an uncolored (gray) core. They are round, 16.4 mm in diameter, 1.4 mm thick, and weight about 4 grains. Strictly speaking, they are not 'tokens.' They are 'points' that were used in conjunction with, rather than in place of, money, when purchasing designated food items. A specified number of blue 'points' were required to purchase specified amounts of crop foods, such as canned fruits and vegetables, fruit juices, soups, baby foods, dried peas, beans, and preserves. Red ‘points’ were required to purchase animal foods, such as meats, butter, oleo, edible fats and oils, cheese, canned milk, and canned fish. soups, baby foods, dried peas, beans, and preserves."
They are collected, "usually with emphasis upon the distinguishing two-letter alphabet codes they bear. There are 54 documented alphabetical combinations—30 blue and 24 red—involving the letters C, H, T, U, V, X, Y, and occasionally W and M. The ‘rare’ tokens in the set are the red ones bearing MM and MV letter combinations."