The BZX79C27 from Micro Commercial Components is a Zener Diode with Zener Voltage 25.1 to 28.9 V, Zener Current 1 mA, Voltage Forward 0.9 V, Current 2 mA, Current Reverse Reverse Leakage Current:- 0.05 uA. More details for BZX79C27 can be seen below.