The PHOTOCO Rotary Projector Slide Tray is designed to hold up to 100 2x2 slides and is compatible with various brands like GAF, Sawyers, Argus, and Hanimex slide projectors. It is a convenient accessory for organizing and easily changing slides during presentations or viewing sessions. This tray is suitable for rotary slide projectors and is a practical solution for efficiently managing a large number of slides without the need for constant manual handling.