FT240-43 Ferrite toroids can be used as common mode choke, impedance transformer or balun.
You can make excellent impedance transformers in the frequency range from 2 up to 50 MHz as well. Typical applications are end fed antenna impedance transformers, off center fed antenna impedance transformers or 1:1 Balun’s.
Spec se picture
Reference: 41-2053
Brand: Messi & Paoloni
Reference: AWLW-102
Brand: Sotabeams