A generic R75-series receptacle for the 75 mil (1.91 mm) grid with a solder-cup termination. It is pressed into the fixture's probe plate and the spring probe seats in it, so probes can be exchanged during maintenance without any wiring work.
The R-series is the industry-standard pattern most generic 75 mil probes are built to, so a plate drilled for a branded 75 mil body accepts it too. Within the R75 range the trailing letter sets the termination — S for a solder cup, W for a wire-wrap post — and the numeral marks the body length variant, so check the overall length against your plate stack before substituting one R75 for another.
Generic R75 series, for 75 mil (1.91 mm) test-point pitch
