NTC 50D-9 / MF72 5D9 Inrush Current Limiter, Power Thermistor 50 ohm 1Amp 10.5mm disk. NTC 50D-9 / MF72 5D9 Circuit Protection Thermistor, Inrush Current Limiter. THE NTC 5D-9 and MF72 5D9 are identical in specification, just different manufacturers code this item differently.