The "Microsoft Wireless Optical Desktop Receiver 1.0" is a receiver designed by Microsoft to connect wireless keyboards and mice to a computer. Specifically, it's a receiver for older Microsoft wireless optical desktop sets from the early 2000s, typically using a 27 MHz RF signal. These receivers can connect via USB, PS/2, or infrared. 

Key characteristics:

Compatibility: Designed for Microsoft wireless optical keyboards and mice. 

Connectivity: Offers connections via USB, PS/2, and infrared. 

Frequency: Operates on a 27 MHz RF frequency, often found in older Microsoft wireless desktop sets. 

Model Numbers: Examples include X09-23466 and X09-37655. 

Purpose: Used to replace a lost or non-functional receiver in a compatible Microsoft wireless desktop set.