A spring loaded mechanism will allow user to place and secure tip.

The spring shielded probe rod is equipped on the probe base. One end is used to fix the probe, and the other end is a coaxial or triaxial interface to connect the test equipment. The spring shielded probe rod is suitable for measuring weak current, and can be connected to high voltage at the same time. The leakage current is less than 100fA (need to cooperate with the shielding box), and the high voltage can withstand 1000V.