Wiring harnesses allow users to replace the factory radio with an aftermarket radio without cutting any factory wiring. In most cases, the wire harness plugs directly into the vehicle's factory connector that is behind the radio, providing the new aftermarket radio with power and sound. Some wiring harnesses are specifically for non-amplified sound systems and others for amplified sound systems. In some cases, a wiring harness can be used to bypass a factory amplifier. Wiring harnesses will not retain factory features such as steering wheel controls (check "Interfaces" for more feature retention).