Micro Connectors USB 2.0 A (Female) to Micro USB 4 Feet (1.2M) Extension Cable with Power On/Off Switch for Raspberry Pi (RAS-PWR01) Micro Connectors USB extension cord makes it convenient to control your power supply for your raspberry Pi. The Raspberry Pi has no switch, so it's hard to control its power supply except manually plugging and unplugging the power cord, which can be very inconvenient especially in the process of preliminary debugging. This cable is not only necessary for your raspberry Pi or other single board computers, but can also be used for your Mobile phone and other micro USB compatible devices.