These aspects together make up the speaker's model number. For example: a Jensen C8R speaker is eight inches in size, and has a 10 Oz ceramic magnet. All Jensen speakers also include a date and manufacturer's code. Jensen's source code is 220. Accompanying the company specific (EIA) code (220) is the last digit of the year and the 2 digits of the week manufactured, creating a 6 digit code usually imprinted on the speaker edge or the magnet housing. Thus a code of 220534 would denote a Jensen speaker manufactured in either 1955 or 1965 on the 34th week of that year. Most speaker (and other electronic component) manufacturers began adding the last 2 digits of the year in the 1970s, so the 6 digit code became a 7-digit code.