The MMBZ5247C from Micro Commercial Components is a Zener Diode with Zener Voltage 16.66 to 17.34 V, Zener Current 7.5 to 0.25 mA, Voltage Forward 1.2 V, Current Reverse Leakage Current:- 0.1 uA, Power 300 mW. More details for MMBZ5247C can be seen below.