Had a few minutes so took one of these apart today (it had been damaged) and it uses a 1/4 axial part. I thought for fun I would improve the design by using four 200 ohm resistors to decrease the inductance. That was a bust. The capacitance to the case is really bad now. Think a couple of 100 ohm 1206s may fit from the pin to the case.
Added picture showing what not to do.