This particular Swiss knife Bayonet was used on the renowned 7.5 mm. Sturmgewehr 57 (Assault Rifle 57). The "W + F" circled mark indicates assembly by Waffenfabrik Bern. The "V" above the serial number identifies the blade supplier as the firm, Victorinox, located in Schwyz Canton. Maker of the famed Swiss Army knives. This is one of the fancier bayonets ever made (by a country that's neutral in most every war). Made of Stainless Steel. $80!!!!
