[Amps] KAPSCH Capacitor

[Zgieb]

Has anyody any informationon KAPSCH high voltage capacitor ?.
Marked:  KAPSCH Ko.2975,  1000 pf,  Betr. Spg. 20 kV= 
Both side metallic solid cap with axial screw M8.
Brown tubular, fiberglass or bakelite outside material jacket                        Approx. 40 mm diameter and 136 mm long.
Suitable for rf coupling/decoupling ?. What type capacitor, vacuum, ceramic, other one inside this pipe ?.
Probably was using for medium wave airport transmitter the British made. 

Thanks for help
Andy SP6AEG