An immersion blender is a kitchen appliance used to blend ingredients or puree food in the container in which they are being prepared. They are most often used for pureeing soups and emulsifying sauces while leaving the food in the cooking pan. Some can even be used without removing the pan from the stove. Immersion blenders are to be distinguished from tools such as the kitchen blender and the food processor, both of which require that the food be placed into a specialized vessel for processing and the hand mixer which does not chop the food as it is blended. It is also sometimes called a stick blender, wand blender, torpedo blender, electric hand blender or a Bermixer (after the brand name of professional models made by Dito-Electrolux, sometimes misspelled "beurre mixer"). In professional kitchens, where they can be quite a bit larger than in a home kitchen, they may also be affectionately known as a "boat motor."The immersion blender was invented in Switzerland, by Roger Perrinjaquet who patented the idea on March 6th 1950, He calls the new appliance "bamix", an abbreviation of the French "battre et mixer" (beat and mix). The immersion blender has been in use in European professional kitchens since the 1960s, and was adopted for home use in the United States market in the 1980s.Models for home use usually have a shaft size of ten to twelve inches, but models are available for professional kitchens with a shaft size up to two feet. Home-sized models are available in both corded and cordless versions.