The latch lock secures the mated pair without extra hardware, and the polarizing key prevents accidental mis-mating with a non-keyed header — a practical safeguard in multi-connector harnesses where the wrong mate could short a circuit.
The TE part numbers for those terminals vary by wire gauge and plating; the common choices are 1-1827863-1 (tin, 20-24 AWG) and 1-1827863-2 (gold, 20-24 AWG). If the BOM line only lists this housing, the build stops at crimp — confirm the terminal MPN is on the same purchase order.
The closest functional peer in the same Dynamic D-1100 receptacle family is the 1-2333134-5, which carries 30 positions at the same 2.00 mm pitch and 3.30 mm row spacing, also in a dual-row free-hanging housing with a locking ramp. The 28-position 1-1827863-4 uses a latch lock, while the 30-position version uses a locking ramp — both provide positive retention, but the latch is a more familiar feel for field-service techs who expect an audible click. The two-position difference means the 28-position housing fits a harness that needs exactly 28 circuits; the 30-position is the next step up if the wire count grows. No other spec difference — same pitch, same row spacing, same crimp terminal family.