SEM-25 antenna tuner. NSN 5820-12-141-1252. Appears in clean condition. No water damage inside case. Electrical connectors are not damaged. Otherwise sold as-is.
Frequency range 26.00-69.95 MHz.
“SEM-25” is short for “Sender-Empfangsgerät”, which translates from German as “transmitter-receiver”. SEM-25 consisted of various components and this antenna tuner is part of that larger system.