Ceedmon 20 Pieces Clip-on Ferrite Ring Core RFI EMI Noise Suppressor Cable Clip for 3mm/5mm/7mm/9mm/13mm Diameter Cable, Black

Surprisingly useful, and delivered in a timely manner

These are great! Snap them on and done. See my picture for exactly what was in the box, as I'm not sure if it matches the description but seemed pretty close. I've written the sizes on them in the pic if you look close. The 3mm are good for regular car wires, which I used on my headlight wires at the bulb, the larger ones are good for covered cables, as well as smaller wires if you want to try looping them thru a couple times or more. They snap on easily and with a small screwdriver they are easily removed, yet seem to be quite secure when attached. Would buy these again.

I am using these for ham radio transmitter applications. I use digital modes a lot, i.e. FT8. Occasionally I will have an issue where I key up the transmitter and the program goes nuts. Loses its connection to the radio and D to A / A to D converter (Signalink). I suspected the USB connection to the computer was being scrambled.I had bought the Signalink cables for between their TNC and the radio, which contain built-in toroids for RF suppression. But used a plain old USB2 cable I had lying around to save a few bucks. Well, apparently cheaping out burned me. I installed the RF chokes listed here, one on each end of the USB cable (choose an appropriate diameter), and the problems have stopped.I am impressed with the quantity and number of diameters that are include, and that the snaps to close the toroid are openable - so you can reuse these on other devices. Decent quality.

One can never have too many ferrite ring cores. There's always some device that is suffering from RFI and these work well to limit it.

They worked as stated but they break if you squeeze them to get them to close and snap together.I had a couple break because it was hard to get them to latch properly.