20 Pcs Snap on Ferrite Core Cord Ring RFI EMI Noise Filter Suppressor Cable Clip for 3.5mm/5mm/7mm/9mm/13mm Diameter Cable, Black

It really works well

I installed some of these on wires because RF was getting into my router and shutting it down from my ham radio equipment when I ran more then 100 watts and they solved the problem.

Used to reduce interference from led and digital wiring.

Purchased to try to eliminate annoying 80 Meter bleed over onto PC speakers. Looped the audio cable through the (second smallest) filter once, and issue was resolved.Just to see if there was any benefit, I clamped 3 of the largest ones around my RG-8 feedline from the antenna before my coax switch, and looped the RG-58 jumper wire through the 4th one. Since I don't really suffer from local noise, I didn't see any real difference. Not saying the don't help, or might not fix a issue you have, I'm just saying I cant fixes a issue that I don't have.I DID however, see a difference when I used two of the smaller ones clamped around each end of the USB cable that is used for CAT control. Previously, I was getting frequent CAT errors when operating on certain frequencies, which could be resolved by reducing power. Not a problem now! Just clamped two on the cable, one at each end, and was done. If the problem comes back, I'll just use on of the next size up and loop the cable, but it wasn't needed at this time.Still have a couple left, may give them to other local ops, or may keep in case future issues arise for other projects. Price vs value, certainly worth it! Great build quality, without the inflated price-tag of other large retailers. For MY issues, and what I purchased them for, it was a home-run!

Our computer speakers were picking up radio signals in the background. If we had music on low volume, we could also hear the muffled sounds of talk/news radio. Not quite loud enough to hear the words, but enough to bother me, like hearing a neighbor's TV on through an apartment wall.These ferrite cores fixed our problem. It took two on each end of the speaker wires, and for extra protection I put one on the speaker power cable too. I also moved our speakers a couple feet closer to our computer table and coiled up the extra wire with a zip tie to reduce the length of "antenna" the speaker wire was creating. Now I can only hear the radio signal if I put my ear directly on the speaker with nothing playing. I feel like the sound quality of music and movies has also improved somewhat?

Didn’t work for me but great quality tho.

I needed some smaller Ferrites for my electronic keyer's power plus input and output cables. Bought a big bunch cause I never know when I'll need more.

The kit comes with all different sizes. It had four of the size I needed that fit the wires on my headlights, which in my mind should have been plenty (two for each side). They helped with FM radio interference while the vehicle was parked but the noise came back under acceleration. I didn’t try adding more. I didn’t want to load my headlight housings up with these because of limited space and the heat issue with lLED’s. Any more than two on each side looks and is ridiculous anyway.