It uses a 0.250" (6.35mm) pitch — wide enough to handle the 600V rating with adequate creepage without wasting board space.
Rated 12A per circuit at 600V — the 12A figure is per-contact at the stated operating temperature range of -55°C to 105°C. For continuous duty near the upper temperature limit, derate the current per the manufacturer's curve; the 12A rating assumes free-air convection at 25°C. The 600V rating is line-to-line, so this header suits 480VAC industrial bus feeds or 400VDC battery strings with margin. For frequent field-service disconnects, consider the gold-plated sibling in the same series.
This header accepts the matching MLX 42002 female socket contacts (circular, phosphor bronze) and mates with the corresponding receptacle housing. The through-hole solder tails are 0.170" (4.32mm) long, suited for standard 1.6mm PCBs. The single-row, 4-position layout is keyed by the housing geometry, so you can't mis-mate it with a different circuit-count header from the same series.