What are cemented coated wire wound resistors?

Wire wound resistor on ceramic support coated by cement or vitreous enamel are products for many uses in all sectors of power electronics. Range of resistance values and rated power is very wide. In total we have 8 families, 4 cemented and 4 enameled: RC, RS, RCA, RSA, RCPO, RSPO, RCE, RSE.