Husqvarna has existed since 1689; however, it began Outdoor Power Equipment production with chainsaws in 1978 after being aquired by Electrolux. Since then Husqvarna has agressively expanded it's line to become one of the leading global producers of Outdoor Power Equipment.
Husqvarna's international site.
Husqvarna uses a product model and serial to identify equipment. Husqvarna also uses a 9 digit product id (or sku) number that is unique for each product type (changes by year, production changes, etc). Serial numbers have changed styles over the years; but, are a collection of numbers.
Serial: 2002 8642793
Product ID: 966 42 86-00
In order to get correct parts for equipment you should have all three numbers. Some common places, and styles, include:
The style for identification numbers changes between trimmers. Identification numbers are either on a sticker or a metal tag like with chainsaws