Amazon.com: Logitech USB Unifying Receiver, 2.4 GHz Wireless Technology, USB Plug Compatible with all Logitech Unifying Devices like Wireless Mouse and Keyboard, PC / Mac / Laptop - Black : Electronics
Logitech ERGO M575 Wireless Trackball with Smooth Tracking
What can someone do if they've lost the wireless USB connector to their Logitech keyboard and mouse? - Quora
Refurbished: Logitech Recertified 910-001799 M570 Black 5-button 1-wheel USB RF Wireless Laser Trackball - Newegg.com