List of iPod models

The iPod line has been upgraded many times, and each significant revision is called a "generation". Only the most recent (highest numbered) generation and refurbished units of previous generations of the iPod line are available from Apple for each model (Classic, Nano, Shuffle, Touch). Each new generation usually has more features and refinements while typically being physically smaller and lighter than its predecessor, while usually (but not always) retaining the older model's price tag. Notable changes include the touch-sensitive click wheel replacing the mechanical scroll wheel, use of color displays, and flash memory replacing hard disks.