Accessories...wikipedia

Many accessories have been made for the iPod line. A large number are made by third party companies, although many, such as the late iPod Hi-Fi, are made by Apple. Some accessories add extra features that other music players have, such as sound recorders, FM radio tuners, wired remote controls, and audio/visual cables for TV connections. Other accessories offer unique features like the Nike+iPod pedometer and the iPod Camera Connector. Other notable accessories include external speakers, wireless remote controls, protective cases/films and wireless earphones.^[29] Among the first accessory manufacturers were Griffin Technology, Belkin, JBL, Bose, Monster Cable, and SendStation.

Two designs of iPod earphones. The current version is shown on the right.

BMW released the first iPod automobile interface,^[30] allowing drivers of newer BMW vehicles to control an iPod using either the built-in steering wheel controls or the radio head-unit buttons. Apple announced in 2005 that similar systems would be available for other vehicle brands, including Mercedes-Benz,^[31] Volvo,^[32] Nissan, Toyota,^[33] Alfa Romeo, Ferrari,^[34] Acura, Audi, Honda,^[35] Renault, Infiniti^[36] and Volkswagen.^[37] Scion offers standard iPod connectivity on all their cars.
Some independent stereo manufacturers including JVC, Pioneer, Kenwood, Alpine, Sony, and Harman Kardon also have iPod-specific integration solutions. Alternative connection methods include adaptor kits (that use the cassette deck or the CD changer port), audio input jacks, and FM transmitters such as the iTrip—although personal FM transmitters are illegal in some countries. Many car manufacturers have added audio input jacks as standard.^[38]
Beginning in mid-2007, four major airlines, United, Continental, Delta, and Emirates, reached agreements to install iPod seat connections. The free service will allow passengers to power and charge an iPod, and view video and music libraries on individual seat-back displays.^[39] Originally KLM and Air France were reported to be part of the deal with Apple, but they later released statements explaining that they were only contemplating the possibility of incorporating such systems.^[40]