The 2-640385-4: This is a 24-position, single-row header from the MTA-156 series, pitched at 0.156" (3.96 mm). The header is unshrouded, so the mating receptacle relies on its own housing key for alignment — there is no shroud wall to guide the plug.
Tin-plated contacts — cost over cycle count
Tin is the economical choice for a header that sees one or two mating cycles in its life — typical for a board-to-cable harness built once and shipped. The trade-off is that tin frets under vibration after about 25–50 cycles, so if the application requires repeated field disconnect, a gold-plated sibling in the MTA-156 family is the better call.
Active production — no redesign trigger
The product status is Active, meaning TE Connectivity continues to manufacture this part number. There is no end-of-life notice, no last-time buy clock, and no official successor to cross-reference. The base product number is 640385, so any future revision would carry a different dash number — but for now, this exact order code is the current build.