The Molex 0511101850 is an 18-circuit receptacle housing from the Milli-Grid 51110 series, built for 2.00 mm pitch wire-to-board interconnects. The dual-row layout with 0.079" (2.00 mm) row spacing gives a compact 18-position footprint for signal-level harnesses in tight enclosures.
The listing explicitly notes that the female socket terminals must be purchased separately — a common oversight that stalls a harness build if the crimp terminals aren't on the same purchase order. The mating half is a Milli-Grid 51110 header with the same 2.00 mm pitch and 18 circuits; the terminal part number for the receptacle side is the Molex 50394 series crimp contact (verify wire gauge range against your build).