Resist carbon trackingLow resistance brassMax voltage transferMolded from insulated materialFits PN 8473 and PN 8485 distributors onlyRotor assembly for GM E and fits PN 8473 and 8485 distributors only. The cap and rotor of any ignition system must be considered maintenance items. Just as you change the oil and filter of your car, you should always replace the cap and rotor as a set. To make things easy, we now offer these cap and rotor replacement kits.