MERCATOR knives are manufactured in Solingen (Germany) since 1867. They are famous for having equipped the soldiers of the Kaiser Wilhelm II during the first world war. Then they were used during the second world war. The American soldiers who brought them home made the "K55K" a mythical model:
The first K stands for Kaufmann (name of the company founder)
The number 55 indicates the street number where the original factory was located.
The last K refers to the cat (Katz in German) engraved on the handle.