The 1-1939638-3: This is a 26-position, 2-row header from the Dynamic D-1100 series, on a 2.00mm pitch. A detent lock on the shroud gives a positive hold when mated — no separate latch hardware needed.
Board lock keeps the part planted through solder and vibration
This stops the part from shifting during assembly and adds mechanical retention against cable strain in the field. The contact tails are 0.122" (3.10mm) long, tin-plated at 78.7µin (2.00µm) — a standard through-hole length for 1.6mm PCBs.