Faraday DefenseHigh Saturation Ferrite Home EMP Protection, Surge Protection - Mounts to Home, Shop, Office Breaker Panel, Easy Installation for Lightning, Solar Flare, and Surge Protection

These are required if you have a Type 2 Whole House SPD, so that it can increase the protection rating for CME/EMP on that SPD, the Ferrites take the peak E1&E2 transients and flatten out so the SPD can shunt power to ground long enough for upstream breakers/Main Breaker to flip on their own as lines L1&L2 heats up slowly, which shuts the circuit off normally without causing damage to everything else in house.Electricity takes the path of least resistance, so instead of transient(out of form) electricity flowing through entire house it does it right at breaker box so the devices and appliances in house are protected.You can hear the Ferrites when they are working as they will have a hum or buzz.

Cant tell yet if the product will help protect against an EMP. But its better to have it and not need it than need it and not have it.

50% improvement in your TV picture quality

I bought 3 of these to filter a high frequency interference and they work perfectly well

Quick and easy snap onto 4/0 copper wire for 200 AMP service entrance

I can't believe people are buying this. This will NOT stop a EMP nor prevent surges. The listing states that it was made out of "High Frequency Material", there is no such thing. It is just iron that is magnetized.You could buy the same thing for $5.00

Look up clamp on ferrites. That’s what this is.

Please do not waste your money on these. They will not provide the EMP protection stated. These are clamp on ferrites and are typically used to suppress RFI and Common Mode Current of RF. True EMP protection requires a faraday cage. If you want ferrites, they can be purchased for less than a third of this cost from other retailers but take it from a register Professional Engineer in Electrical Engineering and an Amateur Radio Operator, you will need multiple loops (at least 5-8 loops) or multiple (5-8) snap on ferrites of wire passing through the center of the ferrite to achieve effective RF suppression. Don't be a sucker!