SO239 Insulator

One of the insulators in my Nissei RS-40 fell out and I am unable to locate it. The other one looks like it will fall out any day, so I am replacing both instead of having a hollow cavity there and risking having the center conductor shorted out if something were to fall in. This model is slightly tapered (11.50mm at one end, and 11.85mm at the other) so place the smaller end in first as far as it will go. Then the larger end should be flush with the center conductor.