When companies extend their horizons outside their current product lines, they create multiple (or diversified) product lines. This strategy can possibly provide the company protection against competition and give them a larger market share.
An example of a multi-product company is Yamaha Corporation. They produce a wide range of products including pianos, organs, synthesizers/samplers, portable keyboards, silent instruments, guitars, basses, musical instrument amplifiers, percussion instruments, brass instruments, woodwind instruments, saxophones, music production instruments, electronics, semiconductors, sports equipment, and vehicles (i.e. motorcycles and golf carts) as well.