For a film roll 2 ½"" wide. Tank daylight. This tank is a long cylinder in which the film has U-shaped end of the film is secured to the top of the tank, a piston pushes the film downwardly into the tank. There are different versions: the first models have a rubber bulb to stir the liquid, black paint finish is crackled or polished nickel. They are manufactured in various sizes up to 3 ½"" wide. A Super-Carbina (c. 1934) had a slot to remove the backing paper