The 81 3031 from Smiths Interconnect is a Resistor with Resistance 15 to 400 Ohms, Power Rating 10 W, Tolerance ±5%. Tags: Surface Mount, Chip, 15 to 400 Ohms, 10 to 250 Ohms, 40 W, Tab & Cover Thin Film RF Resistor. More details for 81 3031 can be seen below.