It's a free-hanging (in-line) socket that accepts female crimp terminals, with a latch holder on the body that locks into the mating header for vibration-resistant retention.
It's tighter than the common 2.50 mm or 0.100" pitch used on larger power connectors, so the mating header's through-hole or SMT pads sit closer together. For a 4-position housing, the total footprint width across the header is roughly 8 mm plus the header body width, which fits neatly on a compact PCB edge.
The housing ships empty. The female socket crimp terminals that go into each of the 4 cavities are ordered separately — JST part numbers from the same PNI contact family. If you're populating a harness, make sure the BOM line for the crimp contacts is there alongside this housing.
How the 4-Position Compares to the 6-Position Sibling
The PNIRP-06V-S is the 6-position version of the same PNI housing — same 2.00 mm pitch, same latch holder, same natural PBT body, same free-hanging in-line mounting. The only difference is the cavity count: 4 positions on the PNIRP-04V-S versus 6 on the PNIRP-06V-S. If your circuit count is exactly 4, the 4-position housing is the correct BOM match; the 6-position would leave two unused cavities and a wider footprint. Both are active and accept the same crimp terminals.