The GP-2S is a spring-loaded guide pin with a pointed tip, used to locate a PCB in a FixturFab test fixture. The board drops over the pins and the taper draws it into position as it seats, fixing the DUT in X and Y so that probe contact repeats from one cycle to the next.
The pointed tip is the most forgiving of the GP-2 tip styles at pick-up — it finds the hole from further off-centre than an umbrella head, which matters on hand-loaded fixtures. It also has the smallest hole requirement in the family: Studio offers it for DUT tooling holes of 2 mm and up, so it is the pin to reach for when the board's datum holes are tight. The pin is installed as part of the probe-plate assembly.
