What this 20-position right-angle header does
The 2.54 mm pitch matches standard 0.100-inch ribbon-cable IDC receptacles, and the 4-wall shrouding protects the male pins during mating. The latch lock/eject hooks provide positive retention against cable pull, and the keying slot prevents mismating with unkeyed receptacles.
How this compares to the 16-position sibling
The closest functional alternative within the same series is the 2-1761609-6, which shares the same 2.54 mm pitch, right-angle orientation, gold mating finish, and 1 A per contact rating — but carries 16 positions instead of 20.