This roll of, orthochromatic film was a direct competitor to Kodak's Verichrome. The, B-20 designation was Ansco's specific branding for what the rest of the world calls 120 film. It would produce 8 large 6 \times 9 cm negatives if used in a standard box camera of that era, such as your Brownie models or an Ansco Viking. Finding the film still in its original 1940s-era box is a great way to add, context to a vintage camera display.