What it is and where it fits
The Amphenol FCI BERGSTIK II 79821-424HLF is a dual-row, 24-position unshrouded male pin header built for board-to-board stacking at the classic 0.100" (2.54mm) pitch. Through-hole solder tails pass through the PCB and get wave- or hand-soldered — the 0.200" (5.08mm) post length gives enough stand-off for cleaning under the body. All 24 positions are loaded. Contacts are phosphor bronze with 100 µin (2.54 µm) of tin plating on both the mating interface and the solder-tail side, so it is a tin-on-both-surfaces part — appropriate for the signal and low-power duty this series typically sees rather than high-mating-cycle gold applications. The push-pull fastening type means the header itself relies on friction and the socket's locking feature; there is no integral latch on the pin header. Rated 5 A per contact at 110 V, with UL94 V-0 rated black glass-filled polyester housing.
Mating half and stack height
The pin header needs the matching 24-position BERGSTIK II receptacle (IDC or solder socket) to complete the pair. The dual-row 0.100" pitch and 24 positions loaded define the footprint. Verify the socket stack-height against your board-separation requirement — the insulation height is 0.100" (2.54mm).
What the ratings mean for your BOM
The 5 A per circuit rating is the headline figure, but the tin-plated contacts and push-pull fastening type together tell a more complete story: this is a general-purpose signal/low-power header, not a high-mating-cycle or harsh-environment part. The 100 µin (2.54 µm) tin plating on the mating interface is thicker than minimum but still a tin finish — lifecycle will be lower than an equivalent gold-plated part. The 110 V rating is the dielectric withstanding voltage; confirm it clears your circuit's working voltage with appropriate derating margin. UL94 V-0 on the housing satisfies most industrial and consumer equipment flammability requirements without a separate flame-barrier treatment.
Compliance snapshot
The housing meets UL94 V-0 flammability rating. No RoHS, REACH, or UL/CE certification details appear in the current listing.