Black plastic cap covers hot wire. Most cars used red caps (also available) while other had black. Check your car for proper color. Mandatory for detailed restorations.
Ignition Wire Retainers, pair, 61-72 Oldsmobile Correct black plastic spark plug wire retainers for 1961-72 Cutlass and 442, and 1965-75 88, 98, Starfire and Toronado models. Two different sizes for right and left side of engine. Sold as a pair.