Review on Efficient Noise Filtering: 20 Pcs Snap on Ferrite Core Cord Ring for Various Cable Diameters, Black by Nolan White

All sizes included. It had four wires of the size I needed that matched the wires on my headlights, which I figured should have been plenty (two on each side). They helped with the FM radio jamming when the car was parked, but the noise returned on acceleration. I haven't tried to add more. I didn't want to load my headlight housings with it due to space limitations and LED heat issues. In any case, more than two on each side looks ridiculous.