The leather frog made for the Swiss M57 bayonet. In plain English, it means the thingy that you hang on your belt where you put the sheath of your Sturmgewehr 57 bayonet. The bayonet and the sheath are not included.
These are suitable for a max. 35 mm (1 35"") belt. The measurements are c. 180 x 60 mm (7.1" x 2.4"). On the backside, there is the manufacturer’s stamp. At least some of these were made by W. KAUZ in Selzach, but there might also be other manufacturers.
These are in quite a nice condition. They can have minor dents, scratches, and a little dirt. The leather may have gotten a bit stiff in long storage, so you might wanna grease these if you plan on using them.