1.25 mm pitch, 3-position right-angle header for signal-level wire-to-board
The 1734829-3: Rated at 1 A per contact and 125 V, this is a signal interconnect, not a power header.
Shrouded 4-wall housing and UL94 V-0 insulation
The 1734829-3's 1.25 mm pitch is the tightest of the three, which means a denser board layout but also a lower current ceiling (1 A fixed vs the 5 A of the.025 series peer 1376366-8). If your application needs more than 1 A per circuit, the 1376366-8 at 5 A is a better fit, though its 2.20 mm pitch takes more board area.