Several years ago, I bought a VHF frequency meter, that I did not need. However, the price was $5, and I thought the power supply was worth that. I Already had a BC-221 frequency meter, and this power supply is the actual AC supply for the 221.
I plan to use the 221 for checking frequency on the BC-453 that is my Novice receiver, that was previously paired with a Heathkit DX-20 transmitter.