The BZM55C30 from Micro Commercial Components is a Zener Diode with Zener Voltage 28 to 32 V, Zener Current 1.0 mA, Voltage Forward 1.5 V, Current 5.0 mA, Current Reverse Reverse Leakage Current:- 0.1 - 2.0 uA. More details for BZM55C30 can be seen below.