The BZT55C12 from Micro Commercial Components is a Zener Diode with Zener Voltage 11.4 to 12.7 V, Zener Current 1 mA, Voltage Forward 1.5 V, Current 5 mA, Current Reverse Reverse Leakage Current:- <0.1 - <2.0 uA. More details for BZT55C12 can be seen below.