With all my device I’m use only old “ussr” (brandnew) capacitor КВИ2 (KVI2). 100pf 16kv. 

This cap used for ussr military manufacturing. 

It works from -60 to +125 celsium degrees.

Good design for extreme condition with high pulse current and all sessions weather. 

Originally designed to work in pulse circuits. 

Not afraid fast current up or common-mode.

Silverplated ceramic capacitor. 

So good for my customshop baluns!