I am looking for the following, in new or in good used condition:

NATIONAL R-175 R-F PLATE CHOKE

Specifications: The R-175 transmitting R-F Choke is suitable for
parallel feed as well as series-feed circuits in transmitters of
up to 3000 volts plate supply. If plate modulation is not
employed, the chokes may be applied to transmitters operating at
voltages up to 4000.

Thanks,

David Goncalves