0.80mm pitch, 40 positions, four stacking heights
The 2-5177986-1 is a 40-position plug from TE's Free Height (FH) series, built on a 0.80mm pitch with two rows of center strip contacts. It mates with the corresponding FH receptacle to create a board-to-board mezzanine connection at any of four supported stacking heights: 7mm, 11mm, 15mm, or 19mm.
Surface-mount plug with board guide
This plug is surface-mount only, supplied on tape and reel for automated pick-and-place. The built-in board guide aligns the connector during reflow, reducing skew from paste tack or nozzle placement. The 0.270" (6.85mm) height above board leaves clearance for passives or routing traces under the mated assembly when using the 7mm stack height.