What this connector is
The Amphenol FCI BERGSTIK II 86837-124HLF is a 24-position, dual-row board-to-board header in the 0.100-inch (2.54mm) pitch family — the classic pitch that fits the widest range of IDC receptacles and card-edge sockets in industrial automation and instrumentation. It mounts through-hole on a 0.100-inch row grid, carries square male pins rated 5 A per circuit at up to 110 V, and uses a push-pull fastening type — meaning the header relies on its press-fit into the PCB plated-through hole for retention rather than a locking latch. Contacts are gold- or Gold GXT-plated at 30.0 µin (0.76 µm) on the mating side, which puts this firmly in the signal/mixed-duty class rather than a tin-plated power-only header. The insulator is black and rated UL94 V-0, so the housing material passes the self-extinguish test under open flame — a must for harness bundles and enclosed electrical panels where a burning connector could propagate a fault. With 0.380 inches of mating pin length, the header sits deep enough in a matching receptacle to maintain positive contact wipe on insertion. The insulation height matches the 0.100-inch pitch, so in a stack the header-to-receptacle interface holds a consistent z-height at each joint.
Sourcing — it is obsolete
What drives the fit decision
The 24 positions and dual-row configuration are the primary BOM-match criteria — if the board calls for a 24-way dual-row 0.100-inch pitch header, this is the direct slot. The 5 A per circuit rating is per-contact, so a designer routing power on a subset of pins must check the thermal derating curve for the actual current per circuit rather than assuming all 24 pins can carry 5 A simultaneously in a dense dual-row layout. The gold plating grade (30.0 µin) signals extended mating-cycle durability compared to tin-plated equivalents — relevant for field-service or test-fixture applications where the connector sees repeated mate/unmate cycles. The unshrouded, push-pull configuration is the key limitation: there are no polarisation ribs and no locking latch. In a board-to-board stack where vibration or cable pull could unseating the receptacle, the engineer needs to confirm the PCB hole press-fit and any board-level support (a backing plate or jack-screw) are adequate — otherwise specify a shrouded or locking equivalent in the same series.
Where it sits in the series
The BERGSTIK II series spans multiple position counts; the 86837-124HLF is the 24-position member on the base product number 86837. The 2.54mm dual-row footprint is shared across the series, so a designer moving between position counts within BERGSTIK II keeps the same board footprint and row spacing — only the position count changes. This makes series migration straightforward as long as the application does not demand shrouding or keying that only a higher-series housing provides.