The No. 3 Cartridge Kodak is the smallest of the Cartridge Kodak family, taking 4.25 x 3.25 inch (about 11 x 8 cm) picures on daylight loading rollfilm. The No. 4 takes 5 x 4 inch photos and the No. 5 takes 7 x 5 inch pictures. The No. 3 was introduced in April 1900 and dicontinued in 1907. It was never made with a wooden lensboard, like the 4 and 5.

It was an instrument for the more advanced amateur who could afford to spend a few dollars on it. The cheapest version with Triple Action shutter and Rapid Rectilinear lens cost $ 20. From there on there were several costlier shutter/lens combinations, ending at $ 72 for a Volute shutter and Tessar lens. 
 

In the video above you see the No. 3 Cartridge Kodak with its usual film back.

 For all three Cartridge Kodaks plate backs were available. In the video you see the No. 3 with such a back. A plate holder is inserted and a ground glass lies next to the camera. When the ground glass was inserted you had to remove a wooden panel in the back, otherwise you could not see the ground glass.
 

The Cartridge Kodak has a vertical and horizontal sliding lens panel, also the bellows could be extended for macro photos or telephoto shots. If you wanted to use these functions you needed to focus the image on the ground glass. Without it you could not focus properly and also not judge what was on the photo and what not.

The camera in these videos belongs to a very complete set, with both backs, 3 double plate holders, a number of film sheet holders, ground glass, cable release and a leather case in which it all fits.
The lens and shutter are not original, but fitted in about 1910. It all still works well and the image on the ground glass is very clear. It is a superior set and extremely rare in this fine and complete condition.