The 81 3039 from Smiths Interconnect is a Resistor with Resistance 5 to 75 Ohms, Power Rating 20 W, Tolerance ±5%. Tags: Surface Mount, Chip, 5 to 75 Ohms, 14 to 250 Ohms, 100 W, Tab & Cover Thin Film RF Resistor. More details for 81 3039 can be seen below.