Amazon.com: Logitech 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
Best Buy: Logitech USB Unifying Receiver 910-005235
USB Unifying Receiver by Logitech® LOG910005235 | OnTimeSupplies.com
Logitech Unifying + Audio Receiver (981-000963)
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Amazon.com: Logitech 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 USB Unifying Receiver 58 H x 38 W x 14 D Black 910 005235 - Office Depot