Manual bolt hole probes have coils that are positioned at right angles to the probe’s shaft length. The probes are rotated by hand inside the bolt hole with the fastener removed. Standard (fractional and metric) and custom diameters are available with absolute and differential coils.

Manual bolt hole probes are available in an absolute (single coil) configuration with a Microdot connector or in a bridge or bridge differential configuration utilizing a Fischer/LEMO Triax connector. Standard manual bolt hole probes operate between 50 kHz and 500 kHz.

Probes listed feature a plastic tip and body for maximum durability. All probes have a split tip, which enables them to expand beyond the indicated nominal diameter range.