Possession or Receipt of Firearm Not Identified by a Serial Number is a criminal offense in which a person knowingly possesses or receives a firearm without a valid serial number. This type of offense is typically associated with illegal firearms such as those created or modified with the intent of evading law enforcement. It can also refer to firearms that have had their serial numbers removed or defaced. There are two main types of Possession or Receipt of Firearm Not Identified by a Serial Number: manufacturing and trafficking. Manufacturing involves the creation or modification of firearms without serial numbers, while trafficking refers to the buying, selling, or transferring of firearms without valid serial numbers. Both offenses are considered serious crimes and can result in severe penalties.