The 9 positions, all loaded, give you a single-row interconnect for signal or low-power distribution. The 600VAC voltage rating and UL94 V-0 housing make it a fit for industrial control panels and general-purpose equipment inside an enclosure.
How the 640383-9 mates and terminates
This unshrouded header mates with MTA-156 series crimp-socket housings (sold separately). The square male pins (copper alloy) accept the matching crimp terminal. The glass-filled thermoplastic housing holds the pins rigidly.