Logitech Unifying receiver
The Logitech Unifying receiver is a small dedicated USB wireless receiver, based on the nRF24L-family of RF devices, that allows up to six compatible Logitech human interface devices to be linked to the same computer using 2.4 GHz band radio communication. Receivers that are bundled with a Logitech product are paired with the device at the factory. When purchasing a replacement receiver or connecting multiple devices to one receiver, pairing requires the free-of-charge Logitech Unifying software, available for Microsoft Windows and Mac OS X. Although not compatible with Bluetooth, devices pair to Unifying Receivers in a similar way. Peripherals remain paired, and can then be used on systems not supporting the software. Logitech receivers compatible with the Unifying protocol can be identified by the orange Unifying logo, which distinguishes them from Logitech Nano receivers of similar appearance, which pair in a similar manner but only with a single device, without using the Unifying protocol.