Cut down on RFI (radio frequency interference) with this 100 H 2A RF choke. Can be used to make a resonant tuned circuit. This 100uH choke can be the tuning coil for 900 through 3500 kHz. Using a 170pF variable capacitor (the largest section in most clock radios) it tunes approximately 1220 kHz to 3500 kHz Using a 310pF variable capacitor (all sections in most AM/FM tuning capacitors connected in parallel) it tunes approximately 910 kHz to 2700 kHz. Can be used for the tuned circuit in a simple Crystal Radio. 100 microhenrys rated choke will filter out most spuriously generated radio frequency noise. Applications differ with the unit that is receiving the noise consult your schematics. Most often used to get rid of alternator noise in mobile transceivers or any other RF receiver. I bought one for my mobile rig and it is working perfectly the audio from the radio is clear and whine free.