To suit 40 MHZ AM frequency radio kits. Checked to work on 40mhz AM 4 Channel Radios. Works with Futaba and copies (re-branded rcs etc). Single Conversion. Please Note This will not work with all 40mhz kits.If when purchasing the item doesnt work you may return it. Details below. Please note Item is 40mhz AM and not FM. Single Conversion.