Fusible Resistors ( RFU / RFS series ) 1 Instead of printing color codes on the resistors, we mark our logo, production date, resistor value and wattage to the surface of the resistor, so it is easy to read and is traceable. 2.Two sizes:S:The small size, U:Standard size 3.Wattage:S1/4W, S1/2W, S1W, S2W, S3W, 1/6W, 1/4W, 1/3 W, 1/2 W, 1W, 2W 4.Got ISO, UL, SEMKO Certificate and " Green Partner " Certificate from SONY