These are for 4x5 cameras, to use 9x12 film. Here in Europe 9x12 is readily available, and it is a format that I like since I use it too on my classic plate cameras (Avus, Patent Etui...). I have too many holders of this type, so I am selling the surplus. They have little or some signs of use.
Asking 9 Euro per piece, 12 double holders available.