It's a shrouded header with four walls, so the mating receptacle is guided into place and the pins are protected from accidental shorting during handling.
Mounting, locking, and board retention details
The right-angle through-hole termination puts the solder tails on a 0.138" (3.50mm) post length — standard for a 1.6mm PCB thickness with a wave-solder fillet.
ROHS3 compliant, with a UL94 V-2 nylon housing.
If you need a 20-position dual-row variant at the same 4.20mm pitch, the 4-1775099-7 from the ATX series offers 9A per contact with a locking ramp, but its 250VAC rating limits it to lower-voltage applications than the 600VAC of the 2029150-5.