What this connector is
The Amphenol FCI 86503-166HLF is the 66-position member of the BERGSTIK II dual-row header series — a 0.100-inch (2.54 mm) pitch board-to-board header with through-hole solder termination and male square pins. Contact material is phosphor bronze, and the insulation body is black. All 66 positions are loaded. The push-pull fastening type means the header relies on its pin-socket interference fit for retention — there is no locking latch, so this is suited for internal board-to-board stacking in equipment where vibration is low and the mated pair is not routinely disconnected.
Key ratings for selection
Rated 5 A per contact at 110 V — the 5 A headline covers power distribution within the connector row as well as signal duty. The contact finish is 30.0 µin (0.76 µm) of gold over the full mating interface, listed as Gold or Gold, GXT — the thick flash grade gives reconnection cycles well beyond what tin-plated equivalents tolerate. The insulation height of 0.100 inch (2.54 mm) sets the mated stack profile; paired with the 0.100-inch row spacing and 0.250-inch (6.35 mm) mating pin length, the connector sits flat in a mezzanine or right-angle board-stacking arrangement. The post extends 0.120 inch (3.05 mm) below the board surface — confirm your PCB padstack and solder mask opening can accommodate that depth without interference from bottom-side components. UL94 V-0 flammability rating means the housing passes the vertical flame test required in enclosed equipment.
What this connector is used for
Board-to-board signal and low-level power interconnect in industrial control, automation, and instrumentation equipment — the 2.54 mm pitch and dual-row 66-circuit density make this a compact internal stacking header rather than a panel or wire-connector. The unshrouded header exposes the full pin array, so the mating receptacle must carry matching keying or polarization if mis-mate prevention is required. The BERGSTIK II series is widely referenced in industrial automation applications where a through-hole header at standard 0.100-inch grid provides routing predictability on legacy double-sided or multilayer PCBs (K1).