Review on Topnisus [Pack of 10] Clip-on Ferrite Core Ring Bead Cable Clip - Anti-Interference Filter for RFI EMI Noise Suppression, High-Frequency Optimization (5mm Inner Diameter) by Kaushik Sokolowski

Have you ever seen those barrel things on a cable and wondered what they are for? That's it. They are mainly designed to prevent electronic interference both when turning the device on and off. I work at a high school where administrators get walkie-talkies. When the walkie-talkie is activated near the computer, the speakers emit a horrible squeak. Likewise, if I place my phone near the speakers, I occasionally hear a buzzing noise through the speakers as it polls the nearest cell tower. These cores don't completely eliminate radio squeak, but they do a good job of reducing it and eliminating cell phone hum.