The FCI 79821-122HLF is a 22-position, dual-row unshrouded header from the BERGSTIK® II series, built for board-to-board stacking on a standard 0.100" (2.54mm) pitch. All 22 positions are loaded with square male pins in phosphor bronze, finished with 30.0µin (0.76µm) gold or GXT™ on the mating surface — a plating thickness that handles repeated mating cycles without the contact resistance drift you see with thin gold or tin. The through-hole solder tails measure 0.200" (5.08mm) long, and the overall contact length of 0.730" (18.54mm) sets the mated stack height against the matching receptacle. Rated 5A per contact at 110V, with a UL94 V-0 black insulation housing.
What the ratings mean for the fit
The 0.100" pitch is the de facto standard for breadboard and legacy board layouts — the footprint matches a 2.54mm grid, so the board layout is straightforward if your design already uses that pitch. The 5A per contact rating is typical for signal-level current at this pin density; the limiting factor is the temperature rise across the 22 pins in a confined enclosure, not the contact itself. The 30.0µin gold on the mating side is the real differentiator here — it's rated for hundreds of mating cycles without exposing the base phosphor bronze to oxidation, which matters if this header sits in a field-serviceable assembly where the board gets unmated and remated. Unshrouded means the pins are exposed; the mating receptacle must provide the alignment and keying, so check that your receptacle has a polarization feature or the board layout handles the orientation.
Lifecycle and sourcing
The 79821-122HLF carries an Active lifecycle status from the manufacturer — no end-of-life notice, no last-time-buy window. No official replacement or cross-reference is on record, so confirm the BOM position count and the mating half before committing.