The 350742-4 is a 9-position, 3-row, through-hole header from the Universal MATE-N-LOK series.
Pitch, positions, and board footprint
At 6.35mm pitch, the header gives generous room for trace routing between pads on a standard FR4 board — a relief compared to the 4.20mm pitch of the 12-position sibling 1318699-3. The three rows are spaced 6.35mm apart, so the footprint occupies a 12.7mm × 12.7mm square for the pin field. All 9 positions are loaded — no dummy pins to populate. The 0.215" (5.46mm) solder tail length suits a 1.6mm-thick board with a standard wave-solder process.
On a quarterly reconnect schedule, that gold thickness buys decades of reliable contact before the base metal shows.