The 1744037-4: This is a single-row, 4-position header on a 5.08mm pitch — the standard Economy Power spacing for wire-to-board applications up to 7.5A per contact. The shroud has one wall and a friction lock, so the mating receptacle clicks in and stays put under light cable strain.
What the 7.5A rating means on the bench
The 7.5A per contact rating at 250VAC is the maximum continuous current before the temperature rise hits the PA66 housing limit. Derate above 25°C ambient — the operating range goes down to -25°C and up to 105°C, but at the top end the current capacity drops. Tin-on-tin contacts are good for moderate mating cycles; if you need frequent reconnects, the gold-plated sibling in the same series holds up longer.