Logitech Unifying receiver
The Logitech Unifying receiver is an extremely small dedicated USB wireless receiver, based on the nRF24L-family of RF devices, that allows up to six compatible Logitech human interface devices (such as mice, trackballs, trackpads, and keyboards; headphones are not compatible) 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 freely available Logitech Unifying software. Devices pair to Unifying Receivers similar to Bluetooth pairing although the underlying protocols are incompatible.
Each device can pair to one receiver per profile. While most devices only have one profile, newer products such as the Logitech MX Master, MX Anywhere series, and M720 Triathalon, allow multiple profiles. These devices can be connected to multiple receivers simultaneously. This allows the use of different receivers in several computers (e.g., with a desktop and a laptop computer) by simply changing profiles on the mouse. This multi computer function is further augmented by Logitech Flow (software KVM solution) which is similar to Synergy. For other devices, the receiver and input devices can be moved together from one computer to another maintaining their paired status after being unplugged.
Some (older) Unifying devices limit the number of allowable pairing changes to a maximum of 45 times. Once the 45th connection is made, it is no longer possible to connect such a device to a further, different receiver. For users who often switch a Unifying device between multiple PCs or laptops with individual receivers, this connection limit can become an issue. For example, a user who frequently switches a mouse between two receivers (e.g. at work and home) will quickly exhaust the limit of available pairing switches. Newer devices can switch pairings an unlimited number of times.
Pairing software is available for Microsoft Windows and Mac OS X from Logitech. Wireless devices using the Unifying Receiver are supported since Linux 3.2.  Software to manage Unifying devices on Linux is available from third party developers, like Solaar.
In addition, many companies have made USB wireless receivers very similar to Logitech's, though it is unknown if Logitech has taken legal action against these companies or even if Logitech holds a patent for the technology. Logitech devices are incompatible with many of these "off brand" receivers, though some are expressly designed as inexpensive alternatives to the Logitech Unifying receiver that can be paired with Logitech devices.
Logitech Unifying receivers (LURs) are often included in wireless Logitech keyboard, mouse, and combo sets, though they may be purchased alone. As of October 2017, the cost to purchase a LUR directly from Logitech is €12.99, or US$14.99. 
Mousejacking / Keyjacking
Mousejacking, first reported by Bastille Networks, Inc., is the sending of malicious radio signals (packets) wirelessly to an unsuspecting user through Logitech Unifying wireless technology. The exploit takes advantage of a users vulnerable Logitech Unifying receiver and unencrypted signals. Possible exploits include:
- Keystroke Injection by either spoofing a paired mouse or keyboard
- Forced Pairing
Known affected devices include:
- Unifying receiver (USB ID 046d:c52b)
- Unifying receiver (USB ID 046d:c539)
- Logitech G900
- Logitech K360
- Logitech K400r
- Logitech K750
- Logitech K830
Known affected versions of Unifying receiver firmware include but may not be limited to:
Logitech has responded with a few Unifying receiver firmware updates as new exploits have been reported. The latest firmware updates for Windows PCs and Macs can be found here. For Linux users there are native options to flash and experiment with such as fwupd and MouseJack device discovery and research tools. However, with these tools a separate firmware binary is still required. The required .cab files for use with fwupd can be found on the LVFS: Device List. Flashing on a Linux host via a hypervisor such as VirtualBox along with a Windows virtual guest image and Windows executable is also possible.
- "MouseJack device discovery and research tools". Retrieved 17 April 2018.
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- "Linux Git commit: HID: Add full support for Logitech Unifying receivers". Retrieved 2 May 2013.
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- "Logitech Unifying Receiver Connects Multiple Devices to Your Computer". www.logitech.com. Retrieved 2018-03-14.