PTFE insulation copper plating needle test special BNC male to BNC M-M Adapter joint revolution
And cheap BNC adapter main difference:
1 shell copper car, cheap for zinc alloy die casting.
2 insulator for high temperature, high frequency loss of small PTFE material (TELFON, Tie Fulong), generally cheap for ABS material high frequency loss
3 gold-plated needle, contact loss is small, generally cheap imitation gold plating