The FK9B0439ZL from Panasonic Corporation is a MOSFET with Continous Drain Current 13.8 A, Drain Source Resistance 6 to 18 Milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -10 to 20 V, Gate Source Threshold Voltage 1 to 3 V. Tags: Chip. More details for FK9B0439ZL can be seen below.