External cartridge CD changers
These CD changers have one or more separate cartridges that are loaded into the changer. Each cartridge can be removed individually to load, change, or retrieve the disc. They usually hold five to 10 CDs. Six-disc models are the most common. Most models are mounted onto the boot, allowing easy access from the passenger or driver’s seat. Internal cartridge CD changers
These CD changers have cartridges fixed inside the player. Multiple CDs are stored internally and may be retrieved through a single slot. They usually hold five to 10 CDs. They are heavier and take up more space than external cartridge changers, but are also more solid and less prone to CD shake. Carousel CD changers
These CD changers have rotating platters, called carousels, that hold three to seven CDs. The carousel rotates to provide access to all the CDs without ejecting it from the player. Most carousels can also rotate when ejected, allowing the used to change one CD while another is playing. CD jukeboxes
CD jukeboxes copy audio files from CDs and store them in an internal memory, eliminating the need for CD trays or cartridges. They can store up to 2,000 CDs’ worth of audio files. Most models also have a shuffle play feature, which selects and plays random songs from the memory. | 
