It carries a 45 A per-circuit current rating with a 630 V voltage rating, putting it squarely in the power-distribution class — this is not a signal header. The 0.400" (10.16 mm) mating pitch gives ample creepage for the 630 V rating, and the silver-plated mating contacts (100 µ" thickness) handle the high current without the oxide film that limits tin-plated contacts at these levels.
What the 45 A rating and silver plating mean for the build
45 A per circuit is bus-level current — you are wiring this into a DC rail or a motor-drive feed, not a logic line. The silver mating finish (100 µ") is standard for high-current contacts because it stays conductive under repeated thermal cycling; tin at this current would frett and oxidize. The 630 V rating, combined with the 10.16 mm pitch and 4-wall shrouding, gives real isolation — this header can handle mains-level voltages inside an enclosure.
IP20 means it is finger-safe but not sealed — keep it inside the enclosure.
ROHS3 compliance is listed.
The 1-1871673-2 is also a 4-position, dual-row, right-angle through-hole header from the same Dynamic series, but at a 0.098" (2.50 mm) pitch — roughly one-quarter the pitch of the 1-1318983-6. That narrower pitch drops the current rating to a wire-gauge-dependent value well below 45 A, and the voltage rating to 250 VAC/DC. The 1-1871673-2 uses tin-plated mating contacts (31.5 µ") instead of silver. So the choice is straightforward: if you need the 45 A / 630 V headroom and have the board space for the 10.16 mm pitch, the 1-1318983-6 is the part. If your application is lower-power and board-space-constrained, the 1-1871673-2 is the denser alternative.