60 Pcs Black Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3.5 mm 5mm 7mm 9mm 13mm Diameter Cable

They do work, I put them everywhere to help with HF radio communications

I installed a new stereo on my boat and had an alternator whine. In researching for solutions, I found this kit. The ability to have different sizes and options to wrap. The wires was critical because it needed more than just one. They work, and it was a simple fix. Now I have a kit and I am ready for, the next need.

The ferrite mix type is not listed (or I missed it) so you cannot tell the applicable frequency ranges. You with have to assume a common range like 1 to 30 MHz or test with a VNA. Snap clamps make a solid connection.

They work to help reduce Radio Frequency Interference. I wish the package had contained more ferrites for the higher gauge wire. I have an ample supply of smaller ferrites that I cannot use. I'm putting it at 4 stars not because of the quality but because of the quantity of smaller gauge ferrites most consumers will not use.

As good as more expensive items

Very nice assortment of Ferrite Ring Core RFI Noise Suppressors, Large assortment, didn't have to search around to find the one's I needed, all were in this order plus extra for later use.Made for quick and easy installation.

Good deal, but didn't work for me. Used them on led headlights as RFI to cut static for distant stations. Added as many as possible and looped wires inside wherever possible.

The iron cores in these seem to be severely undersized bar magnets and not the proper iron core rings you would normally find. They certainly don't seem to filter any line noise.