The price seems a bit steep for what is essentially a formed piece of bakelite like material, however it is what is needed conveniently home process film in a daylight tank. I have seen plans for a slotted piece of plexigalss that film was wound around and then the whole works was immersed in a paper tray worth of film developer, but it would not be feasible for more than 50' at a time, and all of that had to happen in totla darkness.
The widget for sale - you load the film, pour the chems in, wind the film back and forth to get the chemistry against the emulsion.....