Ferrite Ring Core Ferrite Beads Clip RFI EMI Noise Suppressor Anti-Interference Cable Clip for 3.5mm/ 5mm/ 7mm/ 9mm/ 13mm Diameter Cable, Black (20)

This is a nice assortment of ferrite cores. I'm not sure which mix if material these are but these are usually pretty expensive. This is a really good price for what you get. I had some issues with RF getting into a DVI cable causing the monitor to lose signal and go blank. I used a couple of the larger cores and made a loop in the cable of about 3 or 4 turns and snapped a core on each end of the loop cable bundle. I also put a couple of smaller cores on each end of the cable where it connects to the devices just for good measure and this has significantly helped the problem and has completely solved it in some cases. They do work but you may need to use several cores depending on the specific issue.

These fixed the static noise on the stereo when lights were turned on!

I'm giving these 4 stars because I know they work, and they seem like a quality product, but they didn't solve my issue. I was hearing a buzzing noise from my speakers (not a ground loop hum) when I scrolled my screen or moved my mouse. I tried many different things, including these ferrite rings, using one, and then a few, and even looping the USB cable through a larger one with one and two loops. Nothing made any difference. Balanced audio cable from my DAC to my amp solved the issue.

These worked perfectly to reduce noise in my HF Ham radio. I put them on everything including a led lamp lighting my station and the noise floor dropped dramatically. I appreciate the different sizes and the amount for the price. My sole complaint is they can be hard to lock closed. Once done however, a one time thing, you have a quality choke.

Simple and affordable. I had some slight ground noise on my amplifier and pre amp coming through my ground. I installed these ferrite cores on all my incoming and outgoing cables and the noise is gone.

I appreciate that there is a variety of sizes, and they are easy to put on. In my particular situation, it did not address the issue - a hum in a tube amp probably caused by a ground loop - but for very little effort, it was worth a try and certainly didn't make anything worse.

Works as intended. I was getting high pitch static from HDMI cables next to the shielded audio cable and USB cables. Having multiple of these wrapped around them got rid of all the high frequency noises.

Didn’t make a difference still had the problem