Vacuum Capacitor, Fixed Value 250pF Jennings.
Vacuum Capacitor 250 pF, 10 KV. Great for a linear amplifier project, antenna match. Quite exact value for 40 m yagi gamma match capacitor. Usually gamma rod adjustment is good enough to reach SWR better than 1:1.25 in our experience on three element yagi, boom over 8 m long.
