The MMSZ4713 from Micro Commercial Components is a Zener Diode with Zener Voltage 30 to 31.5 V, Zener Current 50 mA(zener test current), Voltage Forward 0.95 V, Current Reverse Leakage Current:- 0.01 uA, Power 500 mW. More details for MMSZ4713 can be seen below.