The 81 3123TC from Smiths Interconnect is a Resistor with Resistance 10 to 400 Ohms, Power Rating 500 W, Tolerance ±5%. Tags: Tab & Cover, 10 to 400 Ohms, 7 to 250 Ohms, 75 W, Flanged Thin Film RF Resistor. More details for 81 3123TC can be seen below.