This part is a Surface-Mounted Device (SMD) tactile switch from manufacturer GANGYUAN. It has a single-pole single-throw (SPST-NO) operation, and is RoHS compliant for safety. The dimensions of the switch are 3.90mm by 1.55mm by 2.90mm, making it very small and able to fit into limited spaces. This switch is rated to carry up to 50mA of electricity at 12VDC, making it suitable for low-voltage microcontroller applications. The part number of this switch is KAN1542-0291B0201.