Daylight developing tank made for developing medium format roll film (2 ½"). Made by W. Butcher & Sons Ltd. and patterned by George Vere Rowden. Consists of a long tube that unrolls the film in a U-shape. The film is attached to the inside of the tank and unrolls by pushing the rod downwards. This allows for both loading and developing to be done in daylight. Later models (Super-Carbine) had a slot to remove the backing paper. Made in different sizes. Metal body available in black.