The BUK9Y4R4-40E from Nexperia is a MOSFET with Continous Drain Current 91 to 100 A, Drain Source Resistance 3.1 to 8.8 milliohm, Drain Source Breakdown Voltage 40 V, Gate Source Voltage -15 to 15 V, Gate Source Threshold Voltage 0.5 to 2.45 V. Tags: Surface Mount. More details for BUK9Y4R4-40E can be seen below.