This part is an MM3Z10VST1G Zener Diode, which is manufactured by ON Semiconductor. It is a 3-pin, 0.2 watt Zener diode, which is rated for a 2.7 V to 4.7 V reverse breakdown voltage and 2.9 V at 10 mA, with a maximum power dissipation of 200 mW. The device ensures a stable output voltage and a low leakage current. It is also designed for stabilization applications, limiting voltage, and voltage reference in both commercial and industrial systems.