0.156" pitch, 2-position unshrouded header for board-to-wire links
The 644751-2: Its 0.156" (3.96mm) pitch sets the PCB footprint and the per-contact current ceiling, which varies by wire gauge.
The 0.390" (9.91mm) mating pin length provides ample engagement depth for standard MTA-156 crimp receptacles, while the 0.175" (4.45mm) post length suits typical 1.6mm-thick PCBs. Unshrouded design gives direct access to the pins for mating, but lacks the polarisation key of a shrouded header — verify the mating housing orientation during assembly to avoid reverse-mating.
The closest functional sibling is the 640385-2 — same 2-position, right-angle, unshrouded MTA-156 header — which can serve as an AVL alternate if the 644751-2 lead time extends.
Unshrouded vs shrouded: when the keying matters
The 644751-2 is unshrouded, while the 644752-4 in the same series is shrouded with a friction lock. The shrouded version adds polarisation and a locking ramp, which prevents reverse-mating and holds the connector pair under vibration. For a fixed harness in a low-vibration cabinet, the unshrouded 644751-2 is simpler and lower-cost; for a field-service cable that gets cycled regularly, the shrouded 644752-4 is the safer choice.