The GP-2UL is the long-body version of the umbrella-tip spring-loaded guide pin, used to locate a PCB in a FixturFab test fixture. The board drops over the pins and is held in X and Y so that probe travel and landing position stay repeatable across a production run.
Length is the reason to choose it over the standard GP-2U: the longer body suits the taller Dev Pro, Dev Pro XL and Dev Pro XXL cartridge stack-ups, where a standard-length pin would not stand far enough above the plate to catch the board. The umbrella head guides the DUT in and gives it a defined bearing surface. Studio offers it for tooling holes of 2.5 mm and up; installed as part of the probe-plate assembly.
