Snap-in polarizing key for AMP-Latch
The 499991-2 is a snap-in polarizing device for TE Connectivity's AMP-Latch series — a key, plug, or post that keys the connector to prevent mis-mating.
Same-series polarizing options
Within the AMP-Latch accessory family the 499991-2 shares the same snap-in polarizing function as the 499712-1 and the 926329-1 — all three are Bulk-packaged polarizing devices for the same series, so the choice is by inventory or price, not fit.