An item's model number helps identify the type of product issued by a manufacturer, whereas a serial number designates an individual item with a unique code. For example, a group of identical items would have identical model numbers, and a set of serial numbers would be assigned incrementally to each item within that group.
Businesses use part-numbering systems such as model and serial numbers to differentiate between differing products or services. These codes can be a combination of letters, numbers or other symbols as designated by the manufacturer.
A model number is a code used to identify a group of items made in a production run, such as a particular type of blender or vacuum cleaner. Knowing a model number is useful when garnering services for a product's repair since replacement parts often correspond with a model number.
Serial numbers are issued to individual units within a production run. Serial codes - as the name implies - are a unique set of symbols assigned to each product that can help further identify when and by whom the product was made. Issuing companies often maintain a record of serial numbers for reference, which is especially useful for proving the authenticity of a particular item.
Both model and serial codes can often be found engraved, printed or otherwise displayed on a manufactured item or on its packaging.