Powered directly by the tiny electrical impulses emitted by human neurons, neuroiPods do not require batteries and, with no moving parts, never wear out. In theory, a single neuroiPod injected into a human brain could operate as long as the "host" person is alive, or at least non-brain-dead. Since the unit requires no battery, no headphone jack, and no physical user interface (i.e., the LCD screen and control wheel found on larger iPods), the cost-per-unit is surprisingly low - with profit margins for the manufacturer, Apple, proportionally much higher than with other iPod models, including the next-smallest member of the iPod product line, the iPod yocto.