5pcs 42X24X16mm Toroid Core,Ferrite Rings Toroid Core Iron (Black)

These toroids arrived promptly and were undamaged and as described. The size is good for thin coaxial cable and unterminated power lines. These did the trick to eliminate common mode current back into my transciever from a longwire on a 9:1 balun. I also have an air wound choke on the line which lowers, but does not stop common mode current, and which only reduces noice on part of the spectrum. The addition of this toroid to the feedline stopped the CMC and quieted down noise accross the spectrum. If you are looking for a toroid to use on 110ac wires with standard or grounded plugs you will need a larger size, these would be perfect for DC lines from your power supply. I am unsure of the mix, but will attemp to build a few baluns/ununs in the future and see how they perform. This is a great price and they are good toroids.

good Quality

Use these on my HF installation in my truck had some engine noise put these in cleared it right up

Use item rings to contain RFI in my elecrical cables/wiring. Works decently for my cable/wiring usage.

There was a lot of excess electrical noise on my Starlink conversion to 12v. These rings helped calm things down a lot. Now it performs much better.

I used this to wind 6 turns of a USB A to USB B type cable (usually used on printers) for a QDX ham radio 5 watt transceiver. I was having RF problems getting into the computer, and this solved it with no adverse effects on signal. A bit heavy for a light weight portable radio, but solid performance.

Product is as advertised - nice size allowed for easy cable threading. Final solution to a unique problem was to slow a Fluke 8842a’s sample rate down to “S0” to turn on internal analog and digital filters.

Absolutely awful impedance on every frequency. These might be ok for gigahertz applications (i didnt test sweep that far up the spectrum), but for every noise suppression or as a transformer, these are noteworthy in their awfulness. Maybe the manufacturer could post some real technical specs (mix, impedance or loss curves, etc.) so we could understand what these might be useful for?

You have to put both line and neutral or lin and line through the choke.

Alles super.

I misunderstood what they are. They break easily. They are useful.

Calculate size you need before buying. Fun to play with. I glue 3 together to increase inductance before winding voils.

Typical sum ting wong chinese product. Permeability did not match any standard mixes.