The SDC4D18-3R9N-LF from Coilmaster Electronics is a Power Inductor with Inductance 3.9 µH, Inductance Tolerance ±30 %, DCR 155 milli-ohm, Saturation Current 0.88 A, Temperature Operating Range -40 to 125 Degree C. Tags: Surface Mount. More details for SDC4D18-3R9N-LF can be seen below.