The Molex 0511101250 is the 12-circuit receptacle housing from the Milli-Grid 51110 series, a 2.00mm pitch dual-row system built for dense wire-to-board and in-line harness interconnects. The free-hanging (in-line) mount and crimp termination suit it for harness assemblies where the connector lands on a wire bundle, not a PCB.
The 12 positions match a 12-circuit BOM line — count the circuits before committing, because the housing does not have spare cavities. The 2.00mm pitch gives good routing density for signal-level wiring on a 0.062" or 0.093" PCB; the 0.079" row spacing keeps the overall width under 0.25" for the dual-row layout.
The contacts question — what you actually order
The 0511101250 is a housing only. The note on the listing is unambiguous: contacts are not included. You need the matching Milli-Grid female crimp terminal — typically the Molex 50394 series or 50395 series, depending on wire gauge. The housing accepts the terminal after crimping, and the terminal locks into the cavity with a positive retention latch. The 12-position count means 12 terminals for a full populate.