The SHD218409B from Sensitron Semiconductor is a MOSFET with Continous Drain Current -11 to -18 A, Drain Source Resistance 0.20 to 0.22 ohm, Drain Source Breakdown Voltage -100 V, Gate Source Voltage -20 to 20 V, Gate Source Threshold Voltage -2.0 to -4.0 V. Tags: Surface Mount. More details for SHD218409B can be seen below.