7-position MTA-156 header with 4 loaded pins
The 641991-5 is a 7-position header from the MTA-156 series, but only 4 positions are loaded with contacts — the remaining three are empty. The 0.156" (3.96 mm) pitch sets the board footprint and the receptacle spacing — it mates with standard MTA-156 crimp receptacles that use the same pitch. The single-row, shrouded-1-wall design guides the receptacle into alignment without a full shroud.
Friction lock and tin-plated contacts
The 0.650" (16.51 mm) overall contact length gives enough standoff for the receptacle to seat fully.
Peer comparison: 1-292164-1 vs 641991-5
The closest functional peer is the 1-292164-1 from the CT series — also a board-to-cable/wire header with a friction lock, but on a 0.079" (2.00 mm) pitch with 11 positions all loaded. The 641991-5 runs the larger 3.96 mm pitch and only 4 loaded positions; the 1-292164-1 is a denser, fully populated alternative if your board can accommodate the tighter pitch and higher circuit count.