Small Surface Mount Fast Diode 800V 1A (IFSM 30A) 350nS SOD-123F. Cross Reference: FR1K R1800 RS1008 RS1008FL, equivalent for: FR1B FR1D FR1G FR1J FR1L FR1M R1B R1D R1G R1J R1L R1M RS1001FL RS1002FL RS1004FL RS1006FL.