The Amphenol FCI BERGSTIK II 79821-420HLF is a 20-position dual-row board-to-board header at 0.100" (2.54mm) pitch — the classic 2.54 mm grid that fits IDC ribbon-cable connectors, DIL IC sockets, and matching shrouded or unshrouded receptacles across the BERGSTIK family. Contacts are square male pins in phosphor bronze, tin-plated 100 µin (2.54 µm) on the mating face, with 0.430" (10.92 mm) pin engagement length and 0.200" (5.08 mm) post length beyond the board. Rated 5 A per contact at 110 V, the dual-row layout spans 0.730" (18.54 mm) overall contact length and sits in a black UL94 V-0 housing with 0.100" (2.54 mm) insulation height — the stack-height dimension that defines how far the header protrudes above the board surface when fully seated.
What the ratings mean for fit
The 0.100" insulation height is also the row-to-row spacing — the header sits flush at board level with pins protruding 0.100" above the housing, so the mated stack height is governed entirely by what the receptacle contributes. For mezzanine or right-angle board-to-board stacks, confirm the combined stack height lands within your board-separation tolerance.