They are really paper developing trays that can be used for film. They're meant to be used with a minimum of solution in a constant agitation on a motorized base or by hand. If by hand there is a ring on the bottom for the motorized base that prevents easy hand agitation.
They came with three small cups for developer, stop and wash. I owned one and have the paperwork. They can be used for film of course but you need to completely fill the tray for film when it is not being agitated, which from what I remember is up around 1400ml for full coverage. I would not necessarily trust them for good agitation on the motorized base into the corners with minimal solution. It is not a random enough agitation. When completely full they are a pain in the ass to empty for solution changes and get pretty heavy. If you drop it they like to split on the corner seams. Personally for 8x10 film I wouldn't even use it. Even for 4x5 the sheets can move and more then once I found them dislocated. If you get one you need to score the bottom with a utility knife or use drops of glue to keep the film off the plastic bottom or the film will stick to it.