What the 0.250" pitch and right-angle orientation buy the board layout
The 643228-1: The 0.250" (6.35mm) pitch sets the board footprint and the per-contact current ceiling — the wider spacing keeps the temperature rise within the nylon housing limit at the series' rated current. The locking ramp fastening holds the header mated under vibration — the ramp clicks into the mating receptacle and resists back-out from cable tug or machine shake.
Three positions, tin contacts, and the mounting flange
Three positions loaded in a single row — the board footprint is three holes on 0.250" centers, with the mounting flange adding two mechanical anchors outside the signal row for panel or chassis securement.
Solder termination to the PCB — the 0.160" (4.06mm) post length provides enough through-hole protrusion for a reliable solder fillet on standard 1.6mm boards.