The FCI 86837-454HLF is a 54-position, 2-row unshrouded male pin header from the BERGSTIK® II series, on the standard 0.100" (2.54 mm) pitch.
That thickness is standard for tin — it gives enough cycles for a permanent or semi-permanent interconnect inside a chassis, but it is not a high-cycle or corrosive-environment finish.
The 0.100" pitch and 0.100" row spacing match a standard 0.100" x 0.100" grid — the same footprint as a DIP socket or a Berg strip. The overall contact length is 0.600" (15.24 mm), with 0.380" (9.65 mm) on the mating side and 0.120" (3.05 mm) as the solder post. That 0.120" post length is short — it suits a standard 0.062" PCB but may not reach through a thick backplane. The 54 positions in two rows mean the header spans about 2.7" along the board edge, so plan the keep-out zone accordingly.