This was a Christmas present from my sister and it was a big surprise.
Some specs:
A Swiss M1957 knife bayonet for the S.I.G Sturmgewehr 57, very high qulity bayonet, the stainless steel blade is 239mm (9 1/2") This bayonet was designed to be used on the export variants of the Swiss SIG SG510-4 (Stgw 57), in production from about 1957 to about 1983