This is a repair part for Logitech/Logicool mice. It is a spring for the wheel click switch (see image 2). The size is approximately φ2mm x 5mm. Because it is quite small, many people lose it when disassembling the mouse. It is compatible with the following mice, but it has not been confirmed for models other than the G502WL, so please replace it at your own risk. G9x M705 MX1100 M950 G502 G500 G500S G700 G700S It will be shipped by standard mail. Thank you.