The 57102-F08-25ULF: The board footprint is tight: 1.00 mm between adjacent pads, which forces a 2-layer breakout for the inner rows unless you route a via per signal. At 2 A the temperature rise stays under 30°C in still air; this is a signal interconnect for parallel data buses, not a power rail.
Gold Flash Mating — Moderate Cycling Duty
The mating surface carries gold flash over copper alloy. The post is tin, which is the solder-side finish; no compatibility issue with standard SAC305 reflow or wave solder. Compare with the 22-position sibling 57102-F08-11ULF and the 20-position 57102-F08-10ULF — same pitch, same current, same gold flash. The 50-position version is the one you pick when the bus width demands 25 differential pairs or 50 single-ended signals on a single connector.