Wirewound resistor are made by winding the resistance wires on the alkaliless ceramic cores, then coated with noncorrosive, heat-proof and humidity-proof material. Cement type is the one with special flameproof cement stuffed in the ceramic case. Small dimension,excellent stability in high temperature,resistant to humidity and shock. Completely insulated character suitable for printed circuit board. Precision resistance values with longer life. In high resistance values,the winding cores will be replaced by power film cores. Super heat dissipation;small linear temperature coefficient. Instant overload capability; low noise figures and low annual shift on resistance values.