A cassette is a light –tight metal container which is designed to hold the X-ray film and intensifying screens in close contact.

Special cassette will also hold a metal stationary grid as well.

The front face, which is of aluminum or plastic, faces the tube. It is hinged to the back section, which is more strongly made and incorporates the pressure pad and a sheet of lead to absorb back-scatter.

Screens and cassette are, of course, made in various sizes to correspond with the standard film sizes.