This is the DC - Type Probe to fit the THX testersa and many others on the market. Includes a cable for aTHX tester.
For use in very confined spaces. Holes, cylinders etc. Length of Probe 3 3/8" ( 86mm ) Room required to press firing button so 4" is about the min dia for practical use.
Maximum Hardness of the Sample 940HV (Vickers)