The Amphenol FCI 79821-140HLF is a 40-position unshrouded male pin header from the BERGSTIK® II series, arranged in two rows on a standard 0.100" (2.54mm) pitch with the same 0.100" row spacing. This is a through-hole solder-terminated board-to-board interconnect — the square pins are phosphor bronze with a gold or Gold GXT™ mating finish at 30.0µin (0.76µm) thickness, rated for 5 A per circuit at 110 V.
The 0.100" pitch and row spacing are the industry-standard grid — your board footprint is a 2x20 pattern of 0.025" square holes on 0.100" centers, which matches decades of legacy layout conventions.
The through-hole solder tails are 0.200" (5.08mm) long, suitable for standard 0.062" to 0.093" PCBs. The overall contact length of 0.730" (18.54mm) gives you a 0.430" (10.92mm) mating interface above the insulator.