These compact sized Toroid Ferrite cores are useful for suppressing EMI/RFI. Applications range from audio/video equipment wiring, R/C installations, and much more.
A tough epoxy conformal coating helps reduce breakage.
For typical common mode EMI/RFI suppression you need to wrap several turns of cable around the bobbin shaped core. Generally speaking, more turns = more suppression.
They aren’t effective in every electrical noise situation, but they are the first line of defense when EMI/RFI problems are encountered. Every tool box should have several of these on hand for those RF special projects that suffer from interference problems.
NOTE: Price is for Quanity of 1