The 2-644861-2: That pitch is shared across the entire MTA-100 series, so the board layout stays consistent whether you're using a 2-position or a larger version.
Friction Lock — Vibration Resistance Without a Secondary Latch
The friction lock on this header provides a positive retention force against the mating receptacle. It's a tactile snap during assembly — you feel it seat — but it's not a secondary lock (TPA). For moderate vibration environments like a control cabinet or consumer appliance, it holds the pair mated without needing a separate latch mechanism.
Shrouded 4-Wall — Pin Protection and Mis-Mate Prevention
The 4-wall shroud surrounds the male pins on all sides.
It is still in regular production with no announced end-of-life or last-time-buy window.