This is a replacement 2.4GHz USB wireless receiver designed for secure and stable connection with compatible wireless keyboards and mice. It provides reliable performance, low latency, and strong anti-interference capability for daily office and home use. The compact nano-sized receiver can remain plugged into your computer's USB port without blocking other ports, making it highly convenient for laptops and desktops. It serves as an ideal replacement for lost, damaged, or broken original receivers, allowing you to continue using your existing devices without full replacement. This receiver is compatible for use with KM900, KB900, MS900, KM7321W, KM5221W, WM527, WM514, MS5320W, KB7221W and other devices supporting the corresponding Secure Link protocol. Setup is simple: insert the receiver into a USB port, install the required pairing software from official support websites, and follow the on-screen instructions to complete device connection. Please verify your device model and protocol compatibility before purchasing to ensure proper functionality.