Zener Diode, Z Voltage Vz (V) - 28V Z Current Iz (mA) - 4.5mA Zener Imp. @ Iz (Ohms) - 44 Ohms Zener Imp. (@ Izk) - 600 Ohms Z Current Izk - 0.25mA Voltage Tolerance - 5% (Over 1,430 Rectron Zener Diode varieties available. Contact us for details.) - 1N5255B