Board fit and footprint basics
The 3-644695-4: That's enough for moderate mating cycles in a controlled environment; for repeated field disconnect, a gold-plated sibling would be a better call. Rated 250 VAC, with current depending on the wire gauge used in the mating half. The UL94 V-0 thermoplastic housing suits equipment inside an enclosure where flame rating is required.
Sourcing and lifecycle status
No official replacement or successor has been issued. The base product number is 644695.
Compared to the CT series header 1-292164-1, this MTA-100 part has a wider pitch (0.100" vs 0.079") and is unshrouded rather than fully shrouded.